Polyurethanes from Vegetable OilsPolyurethanes from Vegetable Oils

polyurethanespolyurethanes• Polyurethane (PUR and PU) is a polymerPolyurethane (PUR and PU) is a polymer composed of a chain of organic composed of a chain of organic units joined units joined

by carbamate (urethane) links. by carbamate (urethane) links. • 2 Mechanical properties eg- high tensile strength & elongation.Mechanical properties eg- high tensile strength & elongation. Thermal properties:- 40-80Thermal properties:- 40-8000c ( both long & short term application).c ( both long & short term application). Hydrolytic stability:- highest resistanceHydrolytic stability:- highest resistance to water at elevated temperature .to water at elevated temperature . Oil,grease and solvent resistance Oil,grease and solvent resistance

The major application of polyurethanes are Coatings Adhesives & sealants Elastomers, etc

characteristics of polyurethane materialscharacteristics of polyurethane materials

Why vegetable oil based polymer ?Why vegetable oil based polymer ? Vegetable oils are excellent but very heterogeneous renewable raw

materials for polyurethanes It gaining popularity due to some attractive properties related to the

specific structure of oils It concerns about the environment and sustainability. Ready availability Inherent bio degradability Some oils like tung (wood) oil have conjugated double bonds, which

tend to polymerize easily when exposed to air. Its composition and price. Price wise, soybean oil, palm oil, and rapeseed oil are the most

attractive for large-scale industrial products.

Polyurethanes are based on:Polyurethanes are based on:

Castor oilCastor oil Soybean oil Soybean oil Fatty Acid Polyols. Polyfunctional Vegetable Oil-based Polyols. Fatty Acid Polyester. Sun flower, canola,corn,etc

Urethane polymer from soybean oilUrethane polymer from soybean oil Oils and fats are triacylglycerols (triglycerides) i.e., esters of glycerin

and different fatty acids. Soy fatty acids are useful for modification of polyurethanes.Soy fatty acids are useful for modification of polyurethanes. Fatty acids can easily be converted to reactive multifunctional Fatty acids can easily be converted to reactive multifunctional

N-alkanolamides.N-alkanolamides. This modification is achieved by base catalysis of oil with This modification is achieved by base catalysis of oil with

diethanolamine to give dialkanol soyamides.diethanolamine to give dialkanol soyamides. Heat resistant Pu foams are obtained from epoxidized soybean Heat resistant Pu foams are obtained from epoxidized soybean

oil ,diethylene glycol,MDI & polyethylene glycol.oil ,diethylene glycol,MDI & polyethylene glycol. Fire resistant & dimensionally stable Pu’s are epoxidized oil, Fire resistant & dimensionally stable Pu’s are epoxidized oil,

halogenated bis phenol, TDI & phenolic resins.halogenated bis phenol, TDI & phenolic resins.

Castor Oil-based Polyurethanes. Glass transition of castor oil/pure MDI may vary with the hydroxyl

number. it is around 5oc when the isocyanate index ([NCO]100/[OH]) was increased to 120, Tg

increased. Properties of polyurethane networks could be modified by

copolymerizing with different monomers to obtain interpenetrating networks.

carbodiimide modified MDI gives Tg with castor oil of around 8oc. Particularly active in the field of interpenetrating networks with

castor oil polyurethanes was the Sperling group. Casting electro-insulating compounds based on crude MDI and filled

castor oil have been used in the electrical industry for encapsulating dry transformers

Polyurethanes from Fatty Acid Polyols. It is It is prepared either from fatty acids by transesterification of the

polyols with glycols and removing glycerin. Such polyols may have lower viscosity but also lower functionality. Properties of a polyurethane from MDI and a polyol obtained by

epoxidation and ring opening with methanol having an OH number of 173 with those made by transesterification of polyol with ethylene glycol.

If one breaks up the triglyceride structure by transesterification with methanol and removes the glycerin.

Primary hydroxyls give more thermally stable urethane bonds but in the case of EG-fatty acid polyurethane, the break up and evaporation of ethylene glycol may have taken place catalyzed by the residual tin-based esterification catalyst.

Segmented PUs from Polyfunctional Vegetable Oil-based Polyols Addition of glycerin Increasing Tg and the rigidity of the vegetable oil-

based polyurethane networks. Glass transition of the soft phase (soy-based matrix) was found to

decrease with increasing soft segment concentration (SSC). Linear Segmented Polyurethane Elastomers from Fatty Acid

Polyester Soft Segments:

Thermoplastic polyurethane elastomers are block copolymers consisting of alternating soft and hard segments.

Hard segments consisted of mixed esters of terephthalic acid and/or dimeric acid with dimerol and ethylene glycol or butane diol.

Soft segments were polytetramethylene oxide diols of a MW weight of 2000.

Effect of the polyol OH number on Tg of PUs from different oils:

Properties of Vegetable Oil-based PUsElectrical Properties: Vegetable oils are fairly non-polar compounds and as such

could be used as a substitute for petrochemical electroinsulating oils.

Electrical and mechanical properties of castor oil and soy-based polyurethanes showed excellent properties, While castor oil gave rubbery polyurethanes, soy-based compounds were glassy.

Castor oil casting compounds displayed higher permittivity.Thermal Stability : It is not high primarily due to the presence of labile

urethane groups. Standard petrochemical polyurethanes based on propylene

oxide are very unstable in the oxidative atmosphere.

Polyurethanes from polyols with primary hydroxyls are more stable than those with secondary OH

Crosslinking density increases thermal stability Ethylene glycol extended polyurethanes from fatty acid

polyols are the least stable The thermal stability of polyurethanes decreased with

crosslinking density

Hydrolytic Stability: Vegetable oils have three ester bonds susceptible to

hydrolysis The urethane bonds also may hydrolyze when exposed to

high humidity to give an amine and carbon dioxide R-NH-COOR’ + HOH -> RNHCOOH + R’OH R-NH-COOH -> RNH2 + CO2

Biodegradability:

polyurethane foams and cast polyurethanes are biodegradable.

It is desirable for packaging materials and materials intended for short useful life.

It is undesirable in engineering materials with long service life.

Polyurethane prepared from polyols from soybean oil, triolein, and linseed oil by the epoxidation route and hydroformylation using respirometry, measures the evolution of CO2 as a result of bacterial activity on the exposed powdered material in soil.

ConclusionConclusion Vegetable oils offer a variety of new structures in polyols

depending on the method of synthesis, resulting in PUs with new properties, suitable for a range of applications.

Currently, vegetable oil polyols must be used in conjunction with petrochemical polyols in flexible foams, but they could be used as sole polyols in other applications.

New structures are continually being developed and properties are being improved.

With time we can expect a dramatic increase in the use of vegetable oil-based polyols in the polyurethane field.

THANKSTHANKS

Live for better Live for better tomorrowtomorrow

References:- Holcapek, M.; Jandera, P.; Zderadicka, P.; Hruba´, L.

“Characterization of triacylglycerol &diacylglycerol composition of plant oils using high-performance liquid chromatography atmospheric pressure chemical ionization mass spectrometry”, J. Chromatogr. A 2003, 1010, 195–215.

Pryde, E. H.; Gast, L. E.; Frankel, E. N.; Carlson, K. D. “Vegetable oils and animal fats as renewable resources for plastics and coatings applications”, Polym.-Plast. Technol. Eng. 1976, 7, 1–26.

D.L.KAPLAN(ED.)”Biopolymers from Renewable resources”,springer,Medford,USA,January 1998