- Prepolymer
unreferenced date October 2010 The term pre polymer refers to a monomer or system of monomers that have been reacted to an intermediate molecular weight state. This material is capable of further polymerization by reactive groups to a fully cured high molecular weight state. As such, mixtures of reactive polymers with un reacted monomers may also be referred to as pre polymers. The term pre polymer and polymer precursor may be interchanged. Lactic acid as a polymer precursor Main polylactic acid Two molecule s of lactic acid can be dehydrated to lactide , a cyclic lactone . A variety of catalyst s can polymerise lactide to either Heterotactis heterotactic or syndiotactic polylactide , which as biodegradable polyesters with valuable inter alia medical properties are currently attracting much attention. Nowadays, lactic acid is used as a monomer for producing polylactic acid PLA which later has application as biodegradable plastic . This kind of plastic is a good option for substituting conventional plastic produced from petroleum oil because of low emission of carbon dioxide . The commonly used process in producing lactic acid is via Industrial fermentation fermentation , and later to obtain the polylactic acid, the polymerization process follows. Category Plastics Category Polyamides Category Polymers Category Polyurethanes Category Soft matter Category Synthetic resins fr Pr polym re ... more details
|
- Tacticity
A heterotactic rm triad in a polypropylene molecule. Diads Two adjacent structural units in a polymer ... diads, a syndiotactic triad rr consists of two adjacent racemo diads and a heterotactic triad rm is composed ... is P sub m sub sup 2 sup or 0.0625 an heterotactic triad is 2P sub m sub 1 P sub m sub or 0.375 a syndiotactic ... more details
|
- Vernon C. Gibson
initiated by diketiminate metal alkoxides The origin of heterotactic stereocontrol , J. Am ... more details
|
- Lactide
polymerized to polylactic acid polylactide using suitable catalysts, with either syndiotactic or a heterotactic ... more details
|
- Lactic acid
lactide to either heterotactic or syndiotactic polylactic acid polylactide , which as biodegradable ... more details
|
- Polylactic acid
can lead to heterotactic PLA which has been found to show crystallinity. The degree of crystallinity ... more details
|
Encyclopedia
top
