Poly network, castor

Since this pioneering work a number of IPNs have been prepared. Poly(styrene) has been used as the second network polymer in conjunction with several other polymers, including poly(ethyl acrylate), poly(n-butyl acrylate), styrene-butadiene, and castor oil. Polyurethanes have been used to form IPNs with poly(methyl methacrylate), other acrylic polymers, and with epoxy resins. 

Nayak, R D.K. Mishra D. Parida K.C. Sahoo M. Nanda S. Lenka P.L. Nayak. Polymers from renewable resources. IX. Interpenetrating polymer networks based on castor oil polyurethane poly(hydroxyethyl methacrylate) Synthesis, chemical, thermal, and mechanical properties. / Appl. Polym. Sci. 1997, 63, 671-679. 

H. Yeganeh and P. Hojati-Talemi, Preparation and properties of novel biodegradable polyurethane networks based on castor oil and poly(ethylene glycol) ,... 

Using this technique, a large variety of polyurethanes have been prepared from different vegetable oils. Natural polyols like castor oil (generally trifunctional) are directly reacted with diisocyanates to obtain branched polyurethanes, although it is difficult to control the reactivity. However, bifunctional castor oil can be polymerised with diisocyanates in the presence of suitable chain extenders and catalysts to produce polyurethanes in a more controlled manner (Fig. 6.4). A castor oil polyol-based polyurethane network can also be prepared from epoxy terminated polyurethane pre-polymer with 1,6-hexamethylene diamine. Epoxy terminated pre-polymer is obtained by the reaction of glycidol and isocyanate terminated polyurethane pre-polymer of castor oil polyol, poly(ethylene glycol) (PEG) and 1,6-hexamethylene diisocyanate. ... 

The chemo-enzymatic synthesis of polyurethanes has been reported through the inter-esterification of castor oil and linseed oil at ambient temperature, using lipase as a catalyst and foUowed by treatment of the inter-esterified product with TDI. In the first step, partial esters are prepared by transesterification of soybean and linseed oils with n-butanol in the presence of lipozyme (a lipase) as the catalyst. The partial esters are then reacted with different diisocyanates to obtain a series of polyurethanes. The reaction of polyhydroxy compounds (transesterification reaction between different compositions of castor oil and glycolysed poly(ethylene terephthalate)) with diisocyanates offers a polyurethane network for new insulating coating applications. ... 

C. S. Sanmathi, S. Prasannakumar and B. S. Sherigara, Interpenetrating polymer networks based on polyol modified castor oil polyurethane and poly(2-ethoxyethyl methacrylate) Synthesis, chemical, mechanical, thermal properties, and morphology , JAppl Polym Sci, 2004,94,1029-34. 

Electrical properties such as conductivity, resistivity, I (current)-V (voltage) characteristics of vegetable oil-based polyurethane nanocomposites are sometimes influenced by nanocomposite formation with a suitable nanomaterial. BaTiOs superfine fibre-filled castor oil-modified polyure-thane/poly(methyl methacrylate) interpenetrating polymer network nanocomposites exhibit an increase in conductivity between insulator and semiconductor with an increase in nanofibre loading. ... 

A series of castor oil polyurethane/poly(methyl methacrylate) interpenetrating polymer networks (IPNs) and gradient IPNs, cured at room temperature, were prepared by a simultaneous IPN method, and nanocomposites with BaTiOs superfine fibre were reported for the systems. A dose-dependent improvement in thermoelectric and mechanical properties was observed in the nanocomposites compared to the pristine systems. 

Triglycerides, Soybean oil. Castor oU, Sunflower oil. Oil-based polymers. Fatty acids, Epoxidized oils. Interpenetrating networks, CrossUnking of oils. Oil-based polyurethanes, OU-hased polyamides. Oil-based polyester-amides. Oil-based alkyd resins. Oil-based polyesters. Oil-based poly(hydroxyalkanoates)... 

Castor oil has found application in the synthesis of interpenetrating polymer networks (IPNs). These materials can be defined as a combination of two polymer networks, at least one of which is synthesized and/or cross-linked in the immediate presence of the other. They are called semi-lPN if just one of the polymers is a network (Athawale et al, 2003). Early reports on castor oil IPNs appeared in 1977 by Yenwo and co-workers. The report discussed the synthesis possibilities via cross-linking of double bonds with sulfur, reaction of hydroxyl groups with diisocyanates, and emulsion polymerizations with saponified ricinoleic acids as emulsifier. Moreover, the IPNs from acrylic polymers, such as polymethyl methacrylate and poly-2-ethoxyethyl methacrylate, and castor oil-based polyurethanes were reported to contribute to the final properties of the material (Cunha et al., 2004 Sanmathi et al, 2004). Incorporation of acrylic moieties into the PU networks increased toughness and thermal properties. In contrast, IPN polyesters derived from castor oil and dibasic acids (e.g. malonic, succinic, glutaric, adipic, suberic, and sebacic acid) were obtained as soft and opaque elastomers (Suthar et al, 2003). 

Cunha FOV, Melo DHR, Veronese VB, Forte MMC. 2004. Study of castor oil polyurethane-poly (methyl methacrylate) semi-interpenetrating polymer network (SIPN) reaction parameters using a 23 factorial experimental design. Mater Res 7 539-543. 

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