Triacylglycerols polymers

Oxidative polymers are formed in autoxidation when the free radicals terminate each other as under autoxidation. When a triacylglycerol molecule breaks down during autoxidation, the partial triacylglycerol molecules are not removed in the deodorization process and can react with each other, forming dimers, trimers, or polymers. 

Some of oxidative polymer molecules may contain a higher amount of oxygen than the triacylglycerol molecule. When these oxidative polymers decompose, they produce free radicals and release some oxygen (34)... 

This chapter deals with polymers synthesized from oilseed sources. However, to provide the reader with an appreciation of the area of renewable, biodegradable polymers and the place within this area that polymers from oil seeds occupy in terms of functionality, price, and acceptability, some other polymers from major renewable sources are also discussed. The most well-known and widely used renewable biodegradable polymers are those from polysaccharides. The principal polysaccharides of interest to polymer chemists are starches and cellulose, both of which are polymers of glucose. In addition to these, fibers, polylactic acid (PLA), and triacylglycerols of oils are of particular interest for the development of biodegradable industrial polymers. 

USE OF NATURALLY FUNCTIONALIZED TRIACYLGLYCEROL OILS IN INTERPENETRATING POLYMER NETWORKS... 

Next we come to phase transitions. Chapter 14 mentions the various phase transitions that may occur, such as crystallization, gas bubble formation, or separation of a polymer solution in two layers it then treats the nucleation phenomena that often initiate phase transitions. Chapter 15 discusses crystallization, a complicated phase transition of great importance in foods. It includes sections on crystallization of water, sugars, and triacylglycerols. Chapter 16 introduces glass transitions and the various changes that can occur upon freezing of aqueous systems. 

The double bonds in soybean oil can be converted to reactive monomers (Khot et al., 2001 Wool et al., 2002a,b). These reactive monomers (maleates) are copolymerized with styrene through free radical mechanism to form rigid thermosetting resins. The maleates are obtained by glycerol transesterification of soybean oil followed by esterification with maleic anhydride. Several triacylglycerol-based polymers and composites were synthesized, and their properties compared. 

Epoxy acids are present in a number of seed oils where they occur as triacylglycerols and in cutins where they occur as polymers of hydroxy acids. They also develop in some seeds on prolonged storage. Acids with a furan unit (another type of cyclic ether) have been identified in plants, in fish oils, and in blood and urine. Synthetic epoxy acids are discussed in Section 10.4.1. 

The presence of the hydroxyl group sometimes leads to their natural occurrence in unusual forms so that in addition to conventional triacylglycerols they may be present as glycerides with more than three acyl groups, as ester waxes, as polymers, or as lactones. 

Othors. Triacylglycerols (triglycerides) (10) (70-72) make up a large part of the storage lipids in animal and plant cells. They are now receiving renewed attention as a candidate feedstock for the production of polymer resins. When liquid at room temperature they are called oils. Commercially important oils are produced from the seeds of soybeans, com (maize), cotton, sunflowers, flax (linseed), rape, castor beans, tung, palms, peanuts, olives, almonds, coconuts, and canola. Over 7.3 million metric tons of vegetable oils are produced in the United States each year, mainly from soybean, flax, and rapeseed. Soy oil alone accounts for 80% of the seed oils produced in the United States. Soy oil contains about 55% linoleic acid (11), 22% oleic acid (12) and 10% palmitic acid (13). 

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