CMCd Final report abstract · cellulose, 15–35% lignin and 25–40% hemicellulose. The commercial...

FINAL REPORT

Value Added of Durian Husks: Synthesis of Carboxymethyl Cellulose from Durian Husk

Assist. Prof. Pornchai Rachtanapun Miss Rungsiri Suriyatem

Department of Packaging Technology, Agro-Industry, Chiang Mai University

CONTENTS Page

Chapter I…Introduction 1 Chapter II…Methodology 5 Chapter III…Result and discusstions 12 3.1 Precent yield of CMC synthesized with sodium hyfroxide 12 3.2 Infrared spectroscopy (IR) 13 3.3 Degree of substitution (DS) 14 3.4 Viscosity 15 3.5 X-ray diffraction (XRD) 16 3.6 Color 18 3.7 Differential scanning calorimetry (DSC) 22 3.8 CMC morphology 24 3.9 Water vapor permeability (WVP) 27 3.10 Sorption isotherm 28 3.11 Mechanical properties 29 Chapter IV…Conclusions 31 Chapter V…References 32 Chapter VI…Appendix 34

CONTENTS OF TABLES Page

Table 1. Color values of cellulose and CMC synthesized with various NaOH concentrations 18

Table 2. Peak temperature (Tm) and phase transition enthalpy (∆H) of cellulose from Durian husk and CMC synthesized with various NaOH concentrations 23

Table 3. Water vapor transmission rate and water vapor permeability for CMC films synthesized with various NaOH concentration (20, 30, 40, 50, and 60% w/v) 28

Table 4. Percent yield of cellulose pulp from Durian husk after grounded with hammer mill 34

Table 5. Percent dryness of cellulose powder from Durian husk 34 Table 6. Percent yield of CMC from Durian husk after synthesized in

carboxymethylation 35 Table 7. Percent yield of the residue on ignition of CMC with various of NaOH

concentrations. 36 Table 8. The intensity (au) achieved from X-ray difraction of cellulose and CMC

powder synthesized with various NaOH concentrations (20, 30, 40, 50 and 60%) 39

Table 9. Weight gain of CMC films synthesized with various NaOH concentrations (20, 30, 40, 50 and 60%) for WVP testing 44

Table 10. Tensile strength (TS) and elongation at break (EB) of CMC films synthesized with 20% NaOH 45



CONTENTS OF TABLES (CONTINUED) Page



Table. 15. Milliequivalent of base required for the neutralization of 1 g CMC 50 Table 16. Weight of 20%NaOH-CMC film specimens (g) contained in the different

of relative humidity desiccators for sorption isotherm testing 51 Table 17. Weight of 30%NaOH-CMC film specimens (g) contained in the different




of relative humidity desiccators for sorption isotherm testing 55

CONTENTS OF FIGURES

Page Figure 1. Percent yield of CMC synthesized with various NaOH concentrations 12 Figure 2. FTIR spectra of native cellulose and CMC synthesized with various NaOH concentrations (20, 30, 40, 50 and 60%) 13 Figure 3. Effect of NaOH concentrations in alkalization reaction on DS of CMC synthesized from durian husk 15 Figure 4. Effect of NaoH concentrations in CMC synthesis and temperature on viscosity of CMC from durian husk 16 Figure 5. X-ray diffractograms of cellulose and CMC synthesized from durian husk on various NaOH concentrations 17 Figure 6. Peak of intensity (au) of CMC synthesized with various NaoH concentrations recorded on X-ray diffractograms 17 Figure 7. L* (lightness) color values of cellulose and CMC synthesized with

various NaOH concentrations 19 Figure 8. a* (redness) color values of cellulose and CMC synthesized with various NaOH concentrations 19 Figure 9. b* (redness) color values of cellulose and CMC synthesized with various NaOH concentrations 20 Figure 10. ∆E (total color difference) values of cellulose and CMC synthesized with various NaOH concentrations 20 Figure 11. WI (whiteness index) values of cellulose and CMC synthesized with various NaOH concentrations 21 Figure 12. The differential scanning calorimetry thermograph of a) cellulose,

CMC synthesized with NaOH concentrations (20, 30, 40, 50 and 60 %) 22

Figure 13. Relationship between NaOH concentrations in carboxymethylation and

Peak temperature (Tm) of CMC 23

CONTENTS OF FIGURES (CONTINUED) Page

Figure 14. Relationship between phase transition enthalpy (∆H) and NaOH

concentration in carboxymethylation 24

Figure 15. Scanning electron micrographs of native cellulose (a) and CMC

synthesized with NaOH concentrations at (b) 20%, (c) 30%, (d) 40%,

(e) 50% and (f) 60% : 3000x 25

Figure 16. Scanning electron micrographs of native cellulose (A) and CMC

synthesized with NaOH concentrations at (B) 20%, (C) 30%, (D) 40%,

(E) 50% and (F) 60% : 3000x 26

Figure. 17. Weight gain of CMC films synthesized with various NaOH concentrations (20, 30, 40, 50 and 60% w/v) 27

Figure 18. Sorption isotherm of CMC films from various NaOH concentrations in carboxymethylation 28

Figure. 19. Tensile strength of CMC films synthesized with various NaOH concentrations (20, 30, 40, 50 and 60% w/v) 29

Figure 20. Percent elongation at break of CMC films synthesized with various NaOH concentrations (20, 30, 40, 50 and 60% w/v) 30

Value Added of Durian Husks: Synthesis of Carboxymethyl Cellulose from Durian Husk

Abstract

Although Durian husk discarded as agricultural waste in Thailand, it has been known as a cellulose source. Cellulose from durian husk was converted to carboxymethylcellulose (CMC) by carboxymethylation using sodium hydroxide (NaOH) and sodium monochloroacetate (SMCA) in isopropyl alcohol (IPA) medium. The reaction was preformed under various amount of NaOH. Infrared spectroscopy (IR), degree of substitution (DS), color, viscosity, x-ray diffraction (XRD), water solubility and differential scanning calorimetry (DSC) of CMCd powder were investigated. Mechanical properties (tensile strength (TS) and elongation at break (EB)), water vapor permeability (WVP) and sorption isotherm of CMC films were also studied. The product has the maximum DS value of 0.87. The structure of resulting polymers was characterized with IR. The optimum condition for carboxymethylation was NaOH amount of 30% (w/v) which provided the highest value of DS and viscosity. The crystallinity of CMCd was declined after synthesis but seemed to be not different in each condition. The L* value of CMC decreased with increased in amount of NaOH (20-40%) since it increased after NaOH amount of 40 to 60%. The trend of a* and b* value were same but be contrary with L* value. This is attributed that the brightness is depend on the DS. The TS of CMC film increases with increasing of NaOH in synthesis but declined at too high amout of NaOH. The EB of CMC film is on the contrary way from the TS.

Key Words: Carboxymethyl cellulose, cellulose, Durian husk, sodium hydroxide

1

CHAPTER I INTRODUCTION

Durian husk is a by-product from the durian preserve industry and fresh

distribution. Durian husk is well known as one of a cellulose sources. Siralertmukul et al. (2005) reported that cellulosic materials polysaccharides can be isolated from durian husk. Functionalized cellulose are strategic in the developments and applications of new biomaterials. The cellulose derivatives are useful, for example, cellulose could be converted by etherification (Kirk and Othmer, 1967). The conversion of plant waste materials into useful products would alleviate a variety of social-economic problems (Pushpamalar et al., 2002). Plant wastes comprise more than 90% (w/w) of carbohydrate polymers (polysaccharides) which are amenable to both chemical and biochemical modifications. The derivative from synthesis by carboxymethylation coveres in wide range of industrial applications. Many polysaccharide derivatives have been prepared by carboxymethylation reactions using varity substances such as cotton linters (Xiquan et al., 1990), starch (Bhattacharyya et al., 1995; Kooijmann et al., 2003), sugar beet pulp (Hasan et al., 2003) cashew tree gum (Silva et al., 2004), papaya peel (Rachtanapun et al., 2005), Mimosa pigra peel (Rachtanapun et al., 2007), sago waste (Pushpamalar et al., 2006).

Cellulose is usually shown in the cell wall of the plants and is generally associated with other substances such as lignin and hemicellulose, which make it difficult to find in pure form. Cellulose is a linear condensation polymer consisting of glucose units joined together by ß–glycosidic bonds between C–4 of one sugar unit and the anomeric C–1 of the other. Plants contain a dry basis between 40–55% cellulose, 15–35% lignin and 25–40% hemicellulose. The commercial versatility of cellulose is such that sometimes it is used in the form of original fibers such as cotton fibers for textile and sometimes it is used in its derivative form such as cellulose nitrate and carboxymethyl cellulose (Thomas et al., 2002; Pushpamalar et al., 2002).

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Carboxymethyl cellulose (CMC) is another important artificial-nature polymer derived from cellulose. CMC is a copolymer of two units: ß–D–glucose and ß–D–glucopyranose 2–O–(carboxymethyl)–monosodium salt, not randomly distributed along the macromolecule, which are linked via ß–1,4–glycosidic bonds. The substitution of the hydroxyl groups by the carboxymethyl group is slightly preponderant at C–2 of the glucose (Charpentier et al., 1997). CMC is widely applied in a lot of industrial sectors including food, paper making, paints, pharmaceutics, cosmetics and mineral processing (Barbucci, Magnani, and Consumi, 2000; Li et al., 2009) due to it is simply and low cost to process. In addition, it is used in other industry such as adhesives (Gayrish et al., 1989), lubricants (Soper, 1991), pesticides (Lee and Farre Torras, 1993), textiles (Kniewske et al., 1994), detergents (Leupin and Gosselink, 1999), ceramics (Sánchez et al., 1999), cements (Ernandes de Brito, 2000), paper (Seiichi and Shosuke, 2000; Tiitu et al., 2006), mango coating (Rachtanapun et al., 2006), and film (Rachtanapun et al., 2005; Cheng et al., 2008). CMC is obtained by activation of the cellulose with aqueous NaOH in slurry of an aqueous organic solvent following reacting the cellulose with monochloroacetic acid. The first step in carboxymethylation is an alkalization where the hydroxyl groups of the cellulose molecules are activated and changed into the more reactive alkaline form (CLL–O–).

CLL–OH + NaOH → CLL–ONa + H2O (1)

This is followed by etherification in the second step (2), and a side reaction (3) also occurs which competes with the production process of carboxymethyl cellulose. Sodium gylocate is produced at the expense of the cellulose derivative in the side reaction (Heinze and Pfeiffer, 1999).

CLL–ONa + Cl–CH2–CO–ONa → CLL–O–CH2–COONa + NaCl (2)

3

NaOH + Cl–CH2–CO–ONa → HO–CH2–CO–ONa + NaCl (3)

There are many researches which studied the production of CMC from agricultural waste as a cellulose sources. CMC from sugar beet pulp cellulose and rheological behaviour of CMC was studied by Togrul and Arslan (2003). Adinugraha et al. (2005) synthesized and characterized sodium CMC from cavendish banana pseudo stem (Musa cavendishii LAMBERT). They found, in alkalization, using 15% NaOH provided the highest DS value of CMC. Pushpamalar et al. (2006) investigated the optimization of reaction conditions for preparing CMC from sago waste. They presented the highest DS value was obtained from using isopropyl alcohol as a solvent and 25% of NaOH concentration in alkalization. Rachtanapun et al. (2005) studied the production of CMC films from papaya peel (CMCp). Also, Rachtanapun et al. (2007) studied the synthesis of CMC and CMC films making from waste of mulberry paper. In addition, Rachtanapun et al. (2007) study the effect of bleaching process on mechanical properties of CMC from papaya peel. They found the percentage of hydrogen peroxide increased with increasing of tensile strength, elongation at break but folding endurance decreased. Furthermore, Rachtanapun et al. (2007) also studied the effect of blend CMC from papaya peel / corn flour films on mechanical properties and WVTR. Waring and Parsons (2001) reported the degree of substitution (DS) of CMC is depended on the monochloroacetic acid concentration, reaction temperature and duration of reaction. The solubility of CMC increases with increasing of DS (Girard et al., 2002). Moreover, Siralertmukul et al. (2005), the modification of CMC from durian husk was studied and the carboxymethylation was carried out under different of monochloroacetic acid which indicated the DS value and the highest DS value of CMC as 0.67.

Therefore, in this study, the effect of NaOH concentrations of CMC synthesized from durian husk on degree of substitution (DS), Infrared spectroscopy (IR), viscosity, crystallinity, morphology, differential scanning calorimetry (DSC), and

4

color were studied. Moreover the effect of NaOH concentrations of CMC film from durian husk on mechanical properties (tensile strength and elongation at break), water vapor permeability (WVP), and sorption isotherm were also investigated.

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CHAPTER II METHODOLOGY

1. Materials

Durian husk was obtained from Taladthai (Bangkok, Thailand). All chemicals used in the preparation and analysis of carboxymethylcellulose (CMC) were AR grade or equivalent. Sodium hydroxide and glacial acetic acid were purchased from Lab-scan; isopropanol, 90% ethanol and absolute methanol from Union science Co., Ltd.; hydrochloric acid and sodium chloride from Merck and monochloroacetic acid from Fluka. 2. Extraction of cellulose

Durian husk was rinsed with water into clean and sun-dried for 4 days. The dried husk was cut into small pieces then it was grounded into powder by a hammer mill (Armfield, England). The powder was cooked with NaOH at 100 °C under pressure 60 PSI. The obtained black slurry was filtered and washed with water. The residue was dried in oven at 55 °C to constant weight for 24 h, and pulp would be provided. The pulp was grounded in grinding machine (Mulinex, England) and bleached with H2O2 at 70 °C for 3 h. It was washed with water and filtered then the pulp was dried again at 55 °C for 24 h (Rachtanapun et al., 2007). The dried pulp was grounded again in the hammer mill to screen into powder with size below 1 mm. and stored in polyethylene bags. 3. Synthesis of carboxymethylcellulose from Durian pulp

About 15.0 g of cellulose powder, 50 ml of various concentrations of NaOH (20, 30, 40, 50 and 60%) and 450 ml of isopropanol were mixed in the beaker for 30 min. The carboxymethylation react was started by adding 18.0 g of monochloroacetic acid and continuously stirred for 30 min. The mixture was covered with aluminum foil

6

and heated up to reaction temperature of 55 °C in an oven for 3.5 h. Then, the mixture was separated into two phases. The liquid phase was removed and the solid phase was suspended in 100 ml of methanol (70% v/v), and neutralized with glacial acetic acid then filtered using Buchner funnel. The final product was washed for 5 times by suspend in 300 ml of ethanol (70% v/v) for 10 minutes to remove undesirable byproducts, and it was finally washed with 300 ml of absolute methanol. The residue from filtration was dried at 55 °C in the oven for overnight (Rachtanapun et al., 2007) and then CMC was obtained. 4. Infrared spectroscopy (IR)

The Infrared spectra were obtained using Infrared Spectophotometer (Bruker, Tensor 27, Germany) using KBr disc technique. Pellets were made from cellulose and CMC samples (~2 mg) with KBr. Transmission were measured at the wave number range of 4000–400 cm-1. The substitution reaction was confirmed by the presence of the COO–, –CH2 and –O– group in the IR spectrum. 5. Degree of substitution (DS)

The degree of substitution (DS) of CMC is the average number of hydroxyl group in cellulose structure which substituted by carboxymethyl and sodium carboxymethyl group at C–2, C–3 and C–6. The DS was determined by USP XXIII method described for Crosscarmellose sodium. The methods include two steps; titration and residue on ignition (Kittipongpatana et al., 2006). The calculation of DS of CMC can use the following equation:

DS = A + S (4)

The degree of acid carboxymethyl substitution (A) can be calculated using Equation. (5):

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A = 1150M / (7120 - 412M - 80C) (5)

The degree of sodium carboxymethyl substitution (S) can be calculated using Equation. (6): S = (162 + 58A)C / (7120 - 80C) (6)

Where M is the net number of milliequivalent of base required for the neutralization of 1 g CMC as determine in titration testing; C is the percentage of residue on ignition of CMC as determine in residue on ignition testing.

6. Color The color characteristic was assessed using a Color Quest XE Spectrocolorimeter (Hunter Lab, USA) to determine L* value (lightness or brightness), a* value (redness or greenness) and b* value (yellowness or blueness) of CMC samples. The colorimeter was warmed up for 30 min and calibrated with a white standard tile: L* = 93.24, a* = −0.72, and b* = 1.53. Measurements were taken for three samples and then average of Hunter L*, a*, and b* value were obtained. Utilizing these Hunter color values, total color difference (∆E) and whiteness index (WI) was calculated as given by Equation. (7) and (8) (Francis and Clydesdale, 1975; Rhim et al. 1999):

(7)

(8)

222 *)(*)(*)(E baL Δ+Δ+Δ=Δ

222 ***)100(100WI baL ++−−=

8

where ∆L*, ∆a* and ∆b* were obtained as differences in L*, a* and b* values of sample with white standard. 7. Viscosity Viscosity of cellulose and CMC was measured using Rapid Visco Analyzer (Model: RVA-4, Newport Scientific, USA). Sample solution was prepared by dissolving 1.0 g of CMC in 25 ml of distilled water (4% w/v) with stirring at 80 °C for 10 min. Viscosity was performed by two steps; in first step, the speed was set at 960 rpm for 10 second, and the second step, the temperature was varied from 30, 40, and 50 °C at 6 min with speed of 160 rpm. All measurements were performed with triplicate. 8. X-ray diffraction (XRD)

X-ray diffraction patterns of cellulose and CMC from Durian husk were recorded in the reflection mode on a JEOL JDX-80-30 X-ray diffractometer. The scattering angle (2θ) was from 10 to 60° at a scan rate of 5 °/min.

9. Differential scanning calorimetry (DSC) The differential scanning calorimeter (DSC, USA) was used to investigate peak temperature or melting temperature (Tm) of cellulose and CMC synthesized with various NaOH concentrations. Heating rate was set at 10 °/min. Sample weight was about 5 mg in a sealed type aluminum pan. After measurement, peak temperatures and enthalpy of melting in DSC thermograph were determined. 10. CMC morphology The scanning electron microscopy (SEM) was studied to analyze the morphology (granule surface and shape) of cellulose and CMC. Morphological

9

investigation of CMC was performed using a scanning electron microscope (SEM), JSM-5910LV (JEOL, USA) at acceleration voltage of 15 kV with 3000x. 11. Film preparation

The 3.0 g of CMC was dissolved in 100 ml of distilled water at 80 °C then constantly stirred for 10 min to prepare the film-forming solution. The solution was cooled down to 25 °C and cast on to cellophane plate (30 cm × 15 cm). Thickness of film was controlled by the volume of solution (70 ml) on each plate. This plate was left and dried at room temperature for 36 h then CMC film was obtained (Rachtanapun et al., 2005). The film was peeled off and kept in dedicator containing silica gel in the bottom to control the moisture content of film. The film was cut for property testing. Mechanical properties (tensile strength and elongation at break) testing required the specimen of 1.5 cm × 14 cm rectangular strips follow by ASTM Method (ASTM, D828-80a, 1995a). Specimen of circle of 7 cm diameter was used for WVP (water vapor permeability) testing. Thickness of the films was measured using a micrometer model GT-313-A (Gotech testing machine Inc., JAPAN). The average of thickness value was used in calculation of tensile strength, elongation at break and WVP.

12. Mechanical properties

Tensile strength (TS) and percentage elongation at break (EB) were determined using Instron Universal Testing Machine Model 1000 (H1K-S, UK). CMC films were preconditioned before used follow by Pachatanapun et al (2007). Initial grip separation and cross-head speed was set at 100 mm and 20 mm/min, respectively. The TS value was calculated by dividing the maximum load with the initial cross-sectional area of the specimen. The EB value was calculated as the percentage of change of the initial gage length of a specimen (100 mm) at the point of a sample failure (ASTM, D828-80a, 1995a).

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13. Water vapor permeability (WVP) The specimen of circle of 7 cm diameter was used for WVP testing by using

the ASTM method (ASTM, E96-93, 1993). The WVP of CMC films was measured as well as circular aluminum cups with diameter of 8 cm and depths of 2 cm were used. The cups containing ten grams of dried silica gel was covered with the specimens and sealed with paraffin wax. Sealed cups were weighted and kept in a desiccator with saturated solution of sodium chloride (NaCl) for providing 25 °C, 75% RH. Then, the cups were weighted everyday for 14 days. Water vapor transmission rate (WVTR) of films was measured from weight gain of the cups and calculated following by Equation (9):

(9) Where film area was 28.27 cm2. The WVP (g.m/m2.mmHg.day) was calculated following by Equation (10):

(10) Where L: the mean of film thickness (mm);

∆P: the partial water vapor pressure difference (mmHg) across the two sides of the film specimen (the vapor pressure of pure water at 25 °C = 23.73 mmHg). 14. Moisture sorption isotherm

CMC film was cut into the size of 30 x 30 mm as a specimen and preconditioned for 7 days at 25 ± 2 °C in desiccators contained silica gel. The specimens were placed in several desiccators contained saturated salt solutions having known relative humidity. LiCl, MgCl2, Mg(NO3)2, NaCl and KCl were used to prepare the saturated salt solutions with achieved the relative vapor pressure of 16, 35, 55, 76 and 99%, respectively. In the desiccators contained NaCl and KCl solutions, a cotton

PLWVTRWVP

Δ•

=

areafilmslopeWVTR =

11

wool bathed of 95% ethanol was used as a fungi static agent. The specimens were weighed daily. ‘‘Equilibrium” was achieved when the change in weight did not exceed 0.1% for three consecutive weightings (Cheng et al, 2008). Percent of equilibrium moisture content was calculated by Equation 11:

(11)

When Wc was film weight constant in saturated salt solutions desiccators.

Wi was film weight before placed in saturated salt solutions desiccators.

15. Statistical Analysis Data were analyzed by one-way analysis of variance (ANOVA) and Ducan's

multiple range test (p = 0.05) using statistica software version 17.

100% xWi

WiWcEMC −=

12

CHAPTER III RESULT AND DISCUSSION

1. Precent yield of CMC synthesized with sodium hyfroxide The cellulose powder from durian husk was modified by carboxymethylation reaction using monochloroacetic acid as an etherifying agent and activation with several amount of NaOH. The percent yield of CMC synthesized with various NaOH concentrations (20, 30, 40, 50 and 60%) were calculated and shown in Figure 1. The result provided that increasing of NaOH concentrations affected to increase the percent yield of CMC. However, the percent yield of CMC slowly declined after NaOH concentration as 40%. This observation could corroborate substitution of carboxymethyl group from carboxymethylation because of the higher molecular weight than hydroxyl group of carboxymethyl group.

Figure 1. Percent yield of CMC synthesized with various NaOH concentrations

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2. Infrared spectroscopy (IR) The infrared spectra were studied to confirm the substitution reaction in

carboxymethylation. The infrared spectra of cellulose from durian husk and CMC synthesized with various NaOH concentrations were presented in Figure 2. Specific vibrations can be found in infrared spectra since this method provide information on molecular vibrations. The cellulose and CMC in each condition were provided the same functional groups. The broad absorption band at 3432 cm-1 is due to the stretching frequency of the –OH group. The band at 2920 cm-1 is due to C–H stretching vibration. The bands around 1420 and 1320 cm-1 are assigned to –CH2 scissoring and –OH bending vibration, respectively. The band at 1060 cm-1 is due to –CH–O–CH2

stretching (Pushpamalar et al., 2006.; Kondo, 1997.; Rachtanapun et al., 2007c)

Figure 2. FTIR spectra of native cellulose and CMC synthesized with various NaOH concentrations (20, 30, 40, 50 and 60%)

From the representative spectrum of all CMC samples synthesized, the strongest absorbances were at 1608, 1419 and 1055 cm-1. This result was indicated the presence of carboxymethyl substituent from CMC synthesis at COO–, –CH2 and –O– group (Adinugraha et al., 2005 and Rachtanapun et al., 2007c). According to Pecsok et al. (1976) and Adinugraha et al. (2005), carboxyl (COO–) groups as its salts have

5001000150020002500300035004000Wavenumber cm-1

020

4060

8010

012

014

0Tr

ansm

ittan

ce [%

]

-OH

C=O

C-H -CH2

-O- — 20%NaOH-CMCd

— 30%NaOH-CMCd

— 40%NaOH-CMCd

— 50%NaOH-CMCd

— 60%NaOH-CMCd

— cellulose-d

14

wave number about 1600–1640 cm-1 and 1400–1450 cm-1. The similar observations have been reported previous by Rachtanapun et al. (2007c), Kittipongpatana et al. (2006) and Adinugraha et al. (2005). This result corroborated that CMC could be synthesized from cellulose of durian husk. 3. Degree of substitution (DS)

CMC which obtained with alkalization of cellulose then followed by carboxymethylation process using sodium monochloroacetate (NaMCA) usually provided DS value in the range of 0.4–1.3. The CMC is fully soluble with its hydro affinity increasing with increasing DS on this range. When the DS is below 0.4, the CMC is swell able but insoluble (Waring and Parsons, 2001).

The effect of various NaOH concentrations in alkalization reaction on DS of CMC synthesized from durian husk was shown in Figure 3. The obtained degree of substitution (DS) from this work was in the range of 0.56–0.87. The DS of CMC increased with increasing in concentration of NaOH and attained a maximum DS of 0.87 at an alkali concentration of 30% (w/v). This finding could be explained by considering the carboxymethylation procedure, where two competitive reactions took place simultaneously. The first involved reaction of the cellulose hydroxyl with NaMCA in the presence of NaOH to give the CMC. The second reaction was the conversions of NaMCA to sodium glycolate as byproduct by react with NaOH (Kirk and Othmer, 1967). This means the first reaction prevails over second reaction up to alkali concentration of 30%. Above this level, there was glycolate formation which means inactivation of NaMCA and its consumption by this side reaction. However, the DS value gradually declined at 40 to 60% NaOH concentrations. This was likely due to the sodium gycolate formation in the synthesis of CMC and polymer degradation was occurred because of high concentration of NaOH. There were found previously the similar observations in maize starch (Khalil et al., 1990), corn and amaranth starch (Bhattacharyya et al., 1995), sago waste (Pushpamalar et al., 2006), cassava starch

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0.56a

0.65e0.67d

0.87b

0.78c

0.4500

0.5500

0.6500

0.7500

0.8500

0.9500

10 20 30 40 50 60 70

%NaOH

Deg

ree

of s

ubst

ititio

n

(Sangseethong et al., 2005), corn starch (Zhou et al., 2007), potato starch (Tijsen et al., 2000) and pigeon pea starch (Lawal et al., 2008).

Figure 3. Effect of NaOH concentrations in alkalization reaction on DS of CMC synthesized from durian husk 4. Viscosity The viscosity of CMC was measured using Rapid Visco Analyzer. The effect of different temperature (30, 40 and 60 °C) and various NaoH concentrations (20, 30, 40, 50 and 60%) in CMC synthesis on viscosity of CMC was shown in Figure 4 and Appendix, Figure 21, 22, and 23. The viscosity of CMC increased with increasing of NaOH concentrations between 20 to 30%, then it slwly decreased with increasing of NaOH concentration up to 60%. In addition, the viscosity of CMC decreased with experiment temperature increased. This is due to the CMC is water-soluble and pseudoplastic-type rheology. Therefore, it provided the higher viscosity value at the lower temperature. This is interestingly that the viscosity trend of CMC similar to the trend of DS value and percent yield of CMC synthesized with various NaOH concentrations.

16

0.00

200.00

400.00

600.00

800.00

1000.00

1200.00

1400.00

1600.00

1800.00

2000.00

0 10 20 30 40 50 60

%NaOH

Visc

osity

(cP)

30°C40°C50°C

Figure 4. Effect of NaoH concentrations in CMC synthesis and temperature on viscosity of CMC from durian husk 5. X-ray diffraction (XRD) X-ray diffractograms of cellulose and CMC from durian husk synthesized with various NaOH concentrations (20, 30,30, 40, 50 and 60%) were presented in Figure 5. CMC samples treated with different NaOH concentrations were less value in a peak of intensity (au) than cellulose. It is shown that after alkalization process with NaOH, the crystallinity of cellulose was reduced. The decrease of crystallinity when the cellulose was treated with NaOH was due to the cleavage of hydrogen bonds because of NaOH. The crystallinity of cellulose was associated with inter- and intra-molecular hydrogen bond of cellulose (Adinugraha et al., 2005). The CMC was water-soluble which lost the crystalline structures in the cellulose granules (Lui, Ruan, Wang and Wu, 2003). According to Fengel and Wegener (1989) this conversion was also resulted in the broadening the distance between cellulose polymer molecules, thus the substitution of NaMCA molecules to the cellulose polymers would be relatively easier than cellulose without alkalization treatment with NaOH. The crystallinity of CMC declinded at 20 to 30%NaOH. The crystallinity of CMC were not significant different at 30 to 60% NaOH. They seemed to be not affected by various NaOH concentrations (Figure 6).

17

900.787b

596.030a

466.629a

580.974a 695.665

ab

1513.352c

0

200

400

600

800

1000

1200

1400

1600

1800

2000

0 10 20 30 40 50 60 70

%NaOH

Inte

nsity

(au)

However, the decrease of the crystallinity was occurred at higher DS of CMC in previous study (Lin et al., 1990).

Figure 5. X-ray diffractograms of cellulose and CMC synthesized from durian husk on various NaOH concentrations

Figure 6. Peak of intensity (au) of CMC synthesized with various NaoH concentrations recorded on X-ray diffractograms

cellulose

18

6. Color Color measurment was carried out in order to determine the color formation that is known to be caused by reaction in carboxymethylation. Color data as the hunter L* (light ness), a* (redness) and b* (yellowness) color value of cellulose and CMC was shown in Table. 1. Color of CMC was changed from milky white into light brown compared with native cellulose. The main effects to color value of CMC were decreased L* (Figure 7) value but increased a* (Figure 8) and b* (Figure 9) value of CMC as NaOH concentrations. This phenomenon was obtained on CMC synthesized with 20% to 40% NaOH concentrations. The decreasing a* and b* value but increasing L* value of CMC as increasing NaOH concentrations were occurred on CMC synthesize with 50 to 60% NaOH concentrations. According to, the lightness, redness, and yellowness of CMC were changed after modification. The color change might be caused from the carboxymethylation reaction. The lightness decreasing; redness and yellowness increasing were obviously occurred in each condition of CMC after modification. Table 1 Color values of cellulose and CMC synthesized with various NaOH concentrations

Type of sample L* a* b* ∆E WI

cellulose 84.60±0.02a 0.00±0.02g 16.81±0.05m 0.00±0.00s 77.20±0.06y

20%NaOH-CMC 83.41±0.01b 0.32±0.01h 19.08±0.03n 2.58±0.02t 74.71±0.03z

30%NaOH-CMC 80.59±0.02c 2.00±0.00i 22.90±0.04o 7.56±0.05u 69.91±0.05A

40%NaOH-CMC 77.61±0.01d 3.49±0.02j 24.61±0.04p 11.04±0.04v 66.55±0.04B

50%NaOH-CMC 79.87±0.02e 2.82±0.02k 22.21±0.04q 7.72±0.03w 69.89±0.04C

60%NaOH-CMC 82.36±0.02f 1.55±0.01l 18.11±0.02r 3.02±0.01x 74.67±0.01D

L*: lightness, a*: redness, b*: yellowness, ∆E: total color difference, WI: whiteness index The L*, a* and b* value of each sample was used to investigated ∆E (total color difference) and WI (whiteness index) value. Then two of above values were calculated and reported. The ∆E (Figure 10) of cellulose and CMC (varios NaOH

19

77

78

79

80

81

82

83

84

85

0 10 20 30 40 50 60 70

%NaOH

L*

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

0 10 20 30 40 50 60 70

%NaOH

a*

concentration) had trend similar to a* and b* value trend. The WI (Figure 11) of cellulose and CMC (varios NaOH concentration) had trend similar to L* value trend. Figure 7. L* (lightness) color values of cellulose and CMC synthesized with various NaOH concentrations Figure 8. a* (redness) color values of cellulose and CMC synthesized with various NaOH concentrations

20

b*

15

17

19

21

23

25

27

0 10 20 30 40 50 60 70%NaOH

0

2

4

6

8

10

12

0 10 20 30 40 50 60 70

%NaOH

∆E

Figure 9. b* (redness) color values of cellulose and CMC synthesized with various NaOH concentrations Figure 10. ∆E (total color difference) values of cellulose and CMC synthesized with various NaOH concentrations

21

WI

65

67

69

71

73

75

77

79

0 10 20 30 40 50 60 70%NaOH

Figure 11. WI (whiteness index) values of cellulose and CMC synthesized with various NaOH concentrations

22

7. Differential scanning calorimetry (DSC) DSC thermograms of cellulose and a carboxymethyl cellulose (CMC) are

presented in Figure 12. The peak temperature and phase transition enthalpy (∆H) were provided in the range of 97.63 to 124.24 oC and 196.97 to 456.36 J/g, respectively. The CMC synthesized with various NaOH concentration obviously provided the decrreasing of ∆H value after modified by carboxymethylation. This result was also occured among all the CMC investigated while the highest ∆H value was observed on the CMC synthesized with 30% NaOH. The trend of ∆H value among all the CMC investigated similar to the trend of DS. Therefore, this phenomenon supported and also could be explained as the finding reported in DS studies.

Figure 12. The differential scanning calorimetry thermograph of a) cellulose, CMC

synthesized with NaOH concentrations (20, 30, 40, 50 and 60 %)

— 20%NaOH-

— 30%NaOH-CMCd

— 40%NaOH-CMCd

— 50%NaOH-

— 60%NaOH-CMCd

— cellulose-d

23

Table 2 Peak temperature (Tm) and phase transition enthalpy (∆H) of cellulose from Durian husk and CMC synthesized with various NaOH concentrations

type of sample Peak temperature (oC) ∆H (J/g)

cellulose 105.00 ± 2.69a 196.97 ± 13.86a

20%NaOH-CMCd 124.24 ± 1.75b 302.31 ± 7.07b

30%NaOH-CMCd 97.63 ± 5.74c 456.36 ± 21.20c

40%NaOH-CMCd 118.89 ± 6.64bd 400.98 ± 35.12d

50%NaOH-CMCd 111.12 ± 2.58ae 370.30 ± 9.97d

60%NaOH-CMCd 114.26 ± 0.82de 365.19 ± 9.62d

Figure 13. Relationship between NaOH concentrations in carboxymethylation and Peak temperature (Tm) of CMC

24

Figure 14. Relationship between phase transition enthalpy (∆H) and NaOH concentration in carboxymethylation 8. CMC morphology

Figure 15 shown the scanning electron micrographs of cellulosed and CMC synthesized with various amount of NaOH (20 (a), 30 (b), 40 (c), 50 (d) and 60 (e) % w/v). Investigation of cellulosed and CMC surface by scanning electron microscopy (SEM) showed that theirs surface were rather rough and theirs fiber were twisted. The surface roughness between cellulosed and CMC in each condition were slighty different. This phenomenon may be caused the cellulosed was extracted and bleached in strongly chemicals before used in carboxymethylation process. Interestingly, CMC synthesized with 40 and 30% NaOH were respectively smoother than the others. This result caused of cellulose crystallinity was changed to allowed the etherifying agent to have higher access to the cellulose molecule for carboxymethylation process (Lawal et al., 2008). However, at 60% NaOH, CMCd surface was crack and untwisted. This

25

reason could be explained that at too high of NaOH concentration in carboxymethylation affected to crystallinity of cellulose structure much decreased. In previous study, there were the smilar presentation as carboxymethy chitosan (Rachtanapun et al., 2008), corn starch (Xiaodong et al., 2002), cassava starch (Qiu et al., 1999), water yam starch (Lawal et al., 2008)

Figure 15. Scanning electron micrographs of native cellulose (a) and CMC synthesized with NaOH concentrations at (b) 20%, (c) 30%, (d) 40%, (e) 50% and (f) 60% : 3000x

a b

c d

e f

26

Figure 16. Scanning electron micrographs of native cellulose (A) and CMC synthesized with NaOH concentrations at (B) 20%, (C) 30%, (D) 40%, (E) 50% and (F) 60% : 3000x

A

D C

B

F E

27

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

day

wei

gth

gain

(g)

20%NaOH-CMCd

30%NaOH-CMCd

40%NaOH-CMCd

50%NaOH-CMCd

60%NaOH-CMCd

9. Water vapor permeability (WVP) The weight gain of CMC films with various NaOH concentrations in

carboxymethylation was shown in Figure 17. This experiment demonstrated that the weight gain of CMC film increased with increasing of experiment time.

Table 3 shown water vapor transmission rate (WVTR) and water vapor permeability (WVP) for CMC films synthesized with various NaOH concentrations (20, 30, 40, 50 and 60% w/v). The WVTR of CMC films were not different in each condition. This result revealed that NaOH was not affected to the WVTR value. The WVP of the CMC film was seperated into two group, one which had higher value and another one had lower value. The higher value of WVP was occurred in the CMC synthesized with NaOH concentration as 20, 50 and 60%. The CMC synthesized with 30 and 40% NaOH were gave the lower WVP value. According to, the WVP was related with film thickness and ∆P, the several of film thickness on each condition may affect for differences of WVP. This observation consistent with previous reports by Rachtanapun et al., 2007b and Tang et al., 2005 (soy protein film).

Figure. 17. Weight gain of CMC films synthesized with various NaOH concentrations (20, 30, 40, 50 and 60% w/v)

28

Table 3. Water vapor transmission rate and water vapor permeability for CMC films synthesized with various NaOH concentration (20, 30, 40, 50, and 60% w/v)

Type of films Thickness (mm) Water vapor Water vapor transmission rate permeability (WVP) (WVTR) (g/day.m2) (g.m/m2.mmHg.day)

20%NaOH-CMC 0.179 ± 0.042 a 50.3714 ± 2.1174 c 5.0747 ± 0.9162 e

30%NaOH-CMC 0.052 ± 0.015 b 49.8408 ± 2.9296 c 1.4656 ± 0.0735 f

40%NaOH-CMC 0.046 ± 0.004 b 47.3883 ± 2.5138 c 1.2183 ± 0.0662 f

50%NaOH-CMC 0.185 ± 0.044 a 41.0565 ± 5.1636 d 4.2320 ± 0.1203 e

60%NaOH-CMC 0.177 ± 0.034 a 45.8672 ± 0.7991 cd 4.5767 ± 0.6967 e

10. Sorption isotherm

Sorption isotherm of CMC films were shown in figure 18. The CMC films with various NaOH concentrations in carboxymethyation demonstrated nonlinear sorption curves due to their hydrophilic property (Nazan Turhan and Sahbaz, 2003; Ayrancı, 1996; Velazquez de la Cruz et al., 2001). In all condition of films, equilibrium moisture content (EMC) increased linearly up to an aw of 0.55–0.76.

Figure 18. Sorption isotherm of CMC films from various NaOH concentrations in carboxymethylation

29

79.617 d53.416 c

255.535 b

140.769 a141.158 a

0

50

100

150

200

250

300

20 30 40 50 60

%NaOH

Tens

ile s

tren

gh (M

pa)

11. Mechanical properties The matherial researches normally focused on the film properties as the mechanical properties such as tensile strength and elongation at break (Cheng et al., 2008; Li et al., 2008; Rachtanapun et al., 2007a,b,c). In this study, rerationship between NaOH concentrations (20, 30, 40, 50 and 60% w/v) in carboxymethylation of CMC and mechanical properties of CMC films were measured and the results were shown in figure 19 and 20. The higher tensile strength was achieved from higher NaOH concentration (20 to 40%) but after 40% its decline was occurred. The result was related to the color value in term of previous experiment. The highest value of tensile strength was presented at CMC synthesized with 40% NaOH which provide the highest a*, b* and ∆E value. In term of elongation at break of CMC film, they were not be significant different between native cellulose and CMC synthesized. Figure. 19. Tensile strength of CMC films synthesized with various NaOH concentrations (20, 30, 40, 50 and 60% w/v)

30

Figure 20. Percent elongation at break of CMC films synthesized with various NaOH concentrations (20, 30, 40, 50 and 60% w/v)

31

CHAPTER IV CONCLUSIONS

In this study, preparation of CMC from Durian husk and effect of NaOH

concentrations on properties of the CMC (DS, IR, viscosity, crystallinity, morphology, DSC and color) and CMC films (mechanical properties, sorption isotherm and WVP) were investigated. The result indicated that the CMC could be synthesized from Durian husk by carboxymethylation. The new band of carbonyl groups (C=O) was occurred by substituent of carboxymethyl groups (CH2COOH) in cellulose chains after modified. The DS value of CMC increased with increasing of NaOH concentration in the range of 20 to 40% and declined after synthesized with 40% NaOH concentration. Also, the brightness of CMC depended on the DS. The crystallinity of CMC decreased after modification and seemed to be not different in each condition. The CMC film with 40% NaOH concentration provided the best mechanical properties. WVP of CMC films was not affected by NaOH concentration.

32

CHAPTER V REFERENCES

Adinugraha, M. P., Marseno, D. W., and Hayadi. (2005). Synthesis and

characterization of sodium carboxymethylcellulose from cavendish banana pseudo stem (Musa cavendishii LAMBERT). Carbohydrate Polymer, 62, 164- 169.

Engsophasnunt., W. (1989). Preparation of Misosa pigra pulp. The bachelor degree research project, Chiang Mai University, Chiang Mai, Thailand.

Fengel, D., and Wegener, G., 1989. Wood: Chemistry, ultrastructure, reactions. Berlin: Walter de Gruyter & Co.

Girard, M., Turgeon, S.L., and Paquin, P. (2002). Emulsifying properties of whey protein–carboximethylcellulose complexes. Journal of Food Science, 67, pp.

113–119. Kirk, R. E., & Othmer, D. F., 1967 (2nd ed) (Vol. 4). Cellulose encylopedia of

chemical technology, New York: Wiley, pp. 593–683. Kittipongpatana , S. O., Sirithunyalug J., and Laenger, R. (2006). Preparation and

physicochemical properties of sodium carboxymethyl mungbean starches. Carbohydrate Polymers, 63, 105–112.

Kniewske, R., Kiesewetter, R., Reinhardt, E., Szablikowski, K., 1994. Preparation of carboxymethyl cellulose and its use in textile printing. DE Patent 92-4239553.

Kondo, T., 1997. The assignment of IR absorption bands due to free hydroxyl groups in cellulose. Cellulose, 4, 281–292.

Lawal, O. S., Lechner, M. D., and Kulicke, W. M., 2008. Single and multi-step carboxymethylation of water yam (Dioscorea alata) starch: Synthesis and characterization, Journal of Biological Macromolecules, 42, 429–435.

Lin, X., Qu, T., and Qi, S., 1990. Kinetics of the carboxymethylation of cellulose in the isopropyl alcohol system. Acta Polymerica, 41(4), 220–222.

33

Lee, M., Farre Torras, M.E., 1993. Pesticidal aqueous cellulose ether solutions. WO Patent 9313657.

Pecsok, R. L., Shields, L. D., Cairns, T., & McWilliam, I. G., 1976. Modern Method of Chemical Analysis. New York, NY: Wiley.

Pushpamalar, V., Langford, S.J., Ahmad, M., and Lim, Y.Y. (2006). Optimization of reaction conditions for preparing carboxymethylcellulose from sago waste. Carbohydrate Polymers, 64, 312–318.

Rachtanapun, P., Kumthai, S., Yagi, N., and Uthaiyod. (2007a). Production of carboxymethylcellulose (CMC) films from papaya peel and their mechanical properties. The proceeding of 45th Kasetsart University Annual Conference, 4, 790-799.

Rachtanapun, P., and Kumthita., Komthita, W. (2007b). Effect of blend CMC from papaya peel / corn flour films on mechanical properties and water vapor permeability. The research project, Chiang Mai University, Chiang Mai, Thailand.

Rachtanapun, P., Mulkarat, N., and Pintajam, N. (2007c). Effect of sodium hydroxide concentration on mechanical properties of carboxymethylcellulose films from waste of mulberry paper. 5 th International Packaging Congress and Exhibition, November 22-24, 2007, Bayrakli-Izmir-Türkiye chamber of chemical engineers-ege branch, Turkey.

Rachtanapun, P., Tiwaratreewit., T. and Suphat Khumthai (2007d). Effect of bleaching process on mechanical properties of carboxymethyl cellulose from papaya peel. Papaya Peel” CMU Research Abstract, November 23-25, 2007, Chiang Mai, Thailand.

Sánchez, E., Sanz, V., Bou, E. and Monfort, E., 1999. Carboxymethylcellulose used in ceramic glazes. Part 3. Influence of CMC characteristics on glaze slip and consolidated glaze layer properties. Ceram. Forum Int. 76 8, pp. 24–27.

34

Tang, C. H., Jiang,Y., Wen, Q. B., Li, L., and Yang, X. Q., 2005. Effect of processing parameters on the properties of transglutaminase-treated soy protein isolate films.

Innovative Food Science and Emerging Technologies, 8, 218−225. Togrul, H., and Arslan, N. (2003). Production of carboxymethyl cellulose from sugar

beet pulp cellulose and rheological behaviour of carboxymethyl cellulose. Carbohydrate Polymers, 54, 73–82.

Waring, M.J., and Parsons, D. (2001). Physico-chemical characterisation of carboxymethylated spun cellulose fibres. Biomaterials, 22, 903-912.

35

CHAPTER VI APPENDIX

Table 4. Percent yield of cellulose pulp from Durian husk after grounded with hammer mill

no. cellulose pulp cellulose powder after grounded (g) %yield 1 80.03 77.67 97.05 2 80.02 78.34 97.90 3 80.01 79.10 98.86

average 80.02 78.37 97.94 Table 5. Percent dryness of cellulose powder from Durian husk

no. cellulose cellulose powder %dryness powder (g) without moisture content (g)

1 1.9997 1.8807 94.04911 2 1.9997 1.8805 94.03911 3 1.9994 1.8805 94.05322

average 1.9996 1.8806 94.04714

36

Table 6. Percent yield of CMC from Durian husk after synthesized in carboxymethylation

%NaOH cellulose (g) CMC (g) %yield of CMC average SD 20.00 25.32 126.60

20 20.00 24.44 122.20 122.22 4.38 20.00 23.57 117.85 20.00 31.36 156.80

30 20.00 34.9 174.50 165.65 8.85 20.00 33.13 165.65 20.00 31.59 157.95

40 20.00 33.38 166.90 162.42 4.48 20.00 32.48 162.40

20.00 28.95 144.75 50 20.00 28.54 142.70 142.72 2.03 20.00 28.14 140.70

20.00 28.34 141.70 60 20.00 26.83 134.15 137.93 3.78 20.00 27.59 137.95

37

Table 7. Percent yield of the residue on ignition of CMC with various of NaOH concentrations.

%NaOH

Crusible CMC Crusible + residue Residue

%Yield of the residue Average weight (g) weight (g) (g) weight (g)

34.7858 1.0171 34.9736 0.1878 18.4664

20 39.5175 1.0544 39.7159 0.1984 18.8125 18.6912

23.0328 1.0325 23.2269 0.1941 18.7946

34.4054 1.0312 34.6955 0.2901 28.1322

30 36.5516 1.0558 36.8475 0.2959 28.0291 28.1114

16.8506 1.0493 17.1462 0.2956 28.1729

31.0954 1.0531 31.3828 0.2874 27.2892

40 38.0596 1.0453 38.3457 0.2861 27.3689 27.3280

32.0227 1.0538 32.3106 0.2880 27.3259

32.3024 1.0361 32.5620 0.2596 25.0603

50 39.1395 1.0229 39.3925 0.2530 24.7277 24.8652

25.0532 1.0411 25.3115 0.2583 24.8077

35.8573 1.0304 36.0900 0.2327 22.5859

60 25.1181 1.0509 25.3523 0.2342 22.2858 22.4655

22.9059 1.0553 23.1436 0.2377 22.5248

38

Figure 21. The viscosity of cellulose and CMC with various NaOH concentration at 30 ºC Figure 22. The viscosity of cellulose and CMC with various NaOH concentration at 40 ºC

Viscosity of CMCd with various NaoH concentrations at 30°C

-500.00

0.00

500.00

1000.00

1500.00

2000.00

2500.00

3000.00

3500.00

3.98 43.98 83.98 123.98 163.98 203.98 243.98 283.98 323.98

Time(s)

Visc

osity

(cP)

0%NaOH-CMCd20%NaOH-CMCd30%NaOH-CMCd40%NaOH-CMCd50%NaOH-CMCd60%NaOH-CMCd


-500.00

0.00

500.00

1000.00

1500.00

2000.00

2500.00

3000.00

3500.00

3.98 43.98 83.98 123.98 163.98 203.98 243.98 283.98 323.98

Time(s)

Visc

osity

(cP)


39

Figure 23. The viscosity of cellulose and CMC with various NaOH concentration at 50 ºC


-500.00

0.00

500.00

1000.00

1500.00

2000.00

2500.00

3000.00

3500.00

3.98 43.98 83.98 123.98 163.98 203.98 243.98 283.98 323.98

Time(s)

Visc

osity

(cP)


40

Table 8. The intensity (au) achieved from X-ray difraction of cellulose and CMC powder synthesized with various NaOH concentrations (20, 30, 40, 50 and 60%)

%NaOH 2Theta (q) Intensity (au) average SD 0 22.275 1263.483 22.025 1649.494 1513.352 216.6829 22.275 1627.079

20 20.395 696.798 20.646 1000.618 900.787 176.6726 20.270 1004.944

30 21.147 483.595 20.744 654.354 596.030 97.39407 20.645 650.140

40 21.272 581.713 20.646 397.668 466.629 100.3177 21.147 420.506

50 21.021 411.797 20.270 628.652 580.974 151.0891 20.020 702.472

60 20.144 604.831 20.270 736.826 695.665 78.77928 20.771 745.337

41

Figure 24. The differential scanning calorimetry thermograph of cellulose from Durian husk

Figure 25. The differential scanning calorimetry thermograph of CMC synthesized with 20% NaOH (w/w)

cellulose

42



43



44

Figure 30. Scanning electron micrographs of a*, *A) cellulose and CMC synthesized with NaOH concentrations at (b*, B*) 20%, (c*, C*) 30%, and (d*, D*) 40%: 50x and 500x, respectively

a* A*

b* B*

c* C*

D* d*

45

Figure 31. Scanning electron micrographs of a*, *A) cellulose and CMC synthesized with NaOH concentrations at (e*, E*) 50% and (f*, F*) 60% : 50x and 500x, respectively Table 9. Weight gain of CMC films synthesized with various NaOH concentrations (20, 30, 40, 50 and 60%) for WVP testing

Day weight gain (g) Type of

films 20%NaOH-

CMC 30%NaOH-

CMC 40%NaOH-

CMC 50%NaOH-

CMC 60%NaOH-

CMC

0 0.0000 0.0000 0.0000 0.0000 0.0000

1 0.8951 1.0172 1.3188 1.2069 1.2453

2 1.4297 1.6491 1.8019 1.7262 1.6970

3 1.9643 2.2811 2.2849 2.2455 2.1487

4 2.3725 2.4922 2.5026 2.5558 2.4441

5 2.5934 2.7142 2.7672 2.7187 2.6385

f* F*

e* E*

46

Table 9. Weight gain of CMC films synthesized with various NaOH concentrations (20, 30, 40, 50 and 60%) for WVP testing (continued)

6 2.6532 2.7545 2.7846 2.7376 2.6725

7 2.6982 2.8140 2.8411 2.7899 2.7242

8 2.6983 2.8030 2.8305 2.7813 2.7182

9 2.7006 2.8029 2.8352 2.7825 2.7201

10 2.7025 2.8048 2.8360 2.7830 2.7207

11 2.7053 2.8077 2.8373 2.7838 2.7217

12 2.7082 2.8107 2.8386 2.7845 2.7226

13 2.7049 2.8076 2.8362 2.7803 2.7193

14 2.7017 2.8045 2.8338 2.7761 2.7159 Table 10. Tensile strength (TS) and elongation at break (EB) of CMC films synthesized with 20% NaOH

no. thickness (mm.) TS EB 1 0.146 128.474 2.501 2 0.128 140.292 1.968 3 0.124 158.957 2.506 4 0.127 144.178 2.304 5 0.137 142.927 2.327 6 0.147 135.605 2.069 7 0.125 144.885 2.072 8 0.139 135.722 2.164 9 0.153 134.928 2.731 10 0.143 145.608 2.618

average 0.137 141.158 2.326 SD 0.010 8.324 0.258

47

Table 11. Tensile strength (TS) and elongation at break (EB) of CMC films synthesized with 30% NaOH


average 0.092 140.769 2.070 SD 0.016 14.430 0.505


no. thickness (mm.) TS EB 1 0.065 227.835 3.017 2 0.061 252.533 2.856 3 0.046 270.978 1.776 4 0.048 298.364 2.045 5 0.043 283.194 1.614 6 0.045 213.333 0.971 7 0.065 289.112 3.419 8 0.050 250.667 1.225 9 0.057 253.329 2.785

48

Table 12. Tensile strength (TS) and elongation at break (EB) of CMC films synthesized with 40% NaOH (continued)

10 0.068 216.010 2.262 average 0.055 255.535 2.197

SD 0.009 30.025 0.812 Table 13. Tensile strength (TS) and elongation at break (EB) of CMC films synthesized with 50% NaOH


average 0.185 53.416 3.133 SD 0.043 8.208 1.488

49



average 0.175 79.617 2.279 SD 0.016 9.755 0.975

50

Table. 15. Milliequivalent of base required for the neutralization of 1 g CMC

%NaOH

CMC weight (g)

HCl Volume

(ml)

NaOH volme (titration)

(ml)

mEq of NaOH

(before titration)

mEq of NaOH

(titration) Sum mEq of NaOH

mEq of HCl mEq require Average mEq

20 1.00 21.20 0.30 2.1663 0.0260 2.1922 2.1200 0.0722 0.0720 1.00 21.10 0.30 2.1663 0.0260 2.1922 2.1100 0.0822

1.00 21.30 0.29 2.1663 0.0251 2.1914 2.1300 0.0614 30 1.01 24.40 0.65 2.1663 0.0563 2.2226 2.4400 -0.2174 -0.2141

1.00 24.30 0.60 2.1663 0.0520 2.2182 2.4300 -0.2118 1.01 24.33 0.62 2.1663 0.0537 2.2200 2.4330 -0.2130

40 1.01 26.60 0.67 2.1663 0.0581 2.2243 2.6600 -0.4357 -0.3872 1.00 26.40 0.70 2.1663 0.0607 2.2269 2.6400 -0.4131

1.00 25.45 0.76 2.1663 0.0659 2.2321 2.5450 -0.3129 50 1.00 27.50 1.20 2.1663 0.1040 2.2702 2.7500 -0.4798 -0.4171

1.00 27.00 1.35 2.1663 0.1170 2.2832 2.7000 -0.4168 1.00 26.25 1.20 2.1663 0.1040 2.2702 2.6250 -0.3548

60 1.00 23.85 0.47 2.1663 0.0407 2.2070 2.3850 -0.1780 -0.1515 1.01 23.74 0.75 2.1663 0.0650 2.2312 2.3740 -0.1428

1.00 23.52 0.60 2.1663 0.0520 2.2182 2.3520 -0.1338

51

Table 16. Weight of 20%NaOH-CMC film specimens (g) contained in the different of relative humidity desiccators for sorption isotherm testing

16% RH 35% RH 55% RH 75% RH weight of sample (g) weight of sample (g) weight of sample (g) weight of sample (g)

day sam. 1 sam. 2 sam. 3 sam. 1 sam. 2 sam. 3 sam. 1 sam. 2 sam. 3 sam. 1 sam. 2 sam. 3 0 0.0443 0.0450 0.0500 0.0484 0.0466 0.0474 0.0446 0.0521 0.0398 0.0404 0.0436 0.0451 1 0.0467 0.0476 0.0529 0.0528 0.0503 0.0516 0.0474 0.0572 0.0435 0.0493 0.0537 0.0554 2 0.0467 0.0472 0.0525 0.0529 0.0503 0.0513 0.0476 0.0572 0.0434 0.0474 0.0510 0.0524 3 0.0485 0.0489 0.0539 0.0531 0.0508 0.0518 0.0480 0.0572 0.0437 0.0468 0.0507 0.0525 4 0.0471 0.0478 0.0529 0.0530 0.0505 0.0516 0.0478 0.0574 0.0435 0.0468 0.0507 0.0522 5 0.0472 0.0480 0.0532 0.0529 0.0504 0.0516 0.0480 0.0572 0.0434 0.0468 0.0506 0.0522 6 0.0471 0.0477 0.0528 0.0529 0.0507 0.0516 0.0480 0.0575 0.0436 0.0475 0.0513 0.0531 7 0.0469 0.0475 0.0527 0.0530 0.0503 0.0514 0.0480 0.0575 0.0436 0.0473 0.0512 0.0526 8 0.0467 0.0472 0.0523 0.0529 0.0504 0.0514 0.0483 0.0577 0.0437 0.0488 0.0524 0.0538 9 0.0469 0.0478 0.0531 0.0522 0.0503 0.0517 0.0477 0.0576 0.0437 0.0468 0.0508 0.0525

10 0.0471 0.0478 0.0529 0.0529 0.0507 0.0516 0.0482 0.0576 0.0439 0.0470 0.0508 0.0530

52




10 0.0342 0.0368 0.0371 0.0411 0.0398 0.0346 0.0388 0.0394 0.0474 0.0420 0.0443 0.0390

53




10 0.0401 0.0385 0.0415 0.0429 0.0490 0.0385 0.0416 0.0404 0.0421 0.0477 0.0445 0.0461

54




10 0.0391 0.0439 0.0464 0.0490 0.0385 0.0357 0.0436 0.0430 0.0474 0.0373 0.0412 0.0471

55




10 0.0453 0.0418 0.0389 0.0402 0.0408 0.0394 0.0469 0.0461 0.0440 0.0477 0.0490 0.0468

CMCd Final report abstract · cellulose, 15–35% lignin and 25–40% hemicellulose. The commercial...

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