INDEX Acetal homopolymer

Many grades of acetal resins are Hsted in Underwriters Eaboratories (UL) Kecogni d Component Directory. UL assigns temperature index ratings indicating expected continuous-use retention of mechanical and electrical properties. UL also classifies materials on the basis of flammability characteristics homopolymer and copolymer are both classified 94HB. 

Products Polymer density in the range 0.912 up to 0.935 for homopolymers the melt index may be varied from 0.2 to greater than 150. Vinyl acetate content up to 30 wt%. 

Classification Homopolymer Definition Homopolymer of vinyl acetate Empirical (C4H602)x Formula [CHzCHOOCOCHaJx Properties Water-wh. clear solid resin sol. in benzene, acetone insol. in water dens. 1.191 ref. index 1.4670... 

The preparation of novel glassy(A)-b-rubbery(B)-l)-crystalline(C) linear triblock copolymers have been reported where A block is PaMeSt, B block is rubbery PIB, and C block is crystalline PPVL. The synthesis was accomplished by living cationic sequential block copolymerization to yield living poly(aMeSt-l)-IB) followed by site transformation to polymerize PVL [243]. In the first synthetic step, the GPC traces of poly(aMeSt-b-IB) copolymers with (w-methoxycarbonyl functional group exhibited bimodal distribution in both refractive index and UV traces, and the small hump at higher elution volume was attributed to PaMeSt homopolymer. This product was fractionated repeatedly using hexanes/ethyl acetate to remove homo PaMeSt and the pure poly(aMeSt-b-IB) macroinitiator was then utilized to initiate AROP of PVL to give rise to poly(aMeSt-b-IB-b-PVL) copolymer. 

The product mix of autoclave and tubular reactors are similar in terms of LDPE homopolymers (0.910-0.935 g/cc) and some specialty grades of polyethylene such as ethylene/vinyl acetate copolymers up to about 30 wt% vinyl acetate (VA). However, the autoclave process provides higher levels of vinyl acetate (40 wt%) in ethylene/VA copolymers and additional specialty grades of polyethylene such as ethylene/methyl acrylate, ethylene/acrylic acid and ethylene/n-butyl acrylate. Polyethylene molecular weight can be varied over a wide range with the high-pressure process, with Melt Index values (I ranging from 0.15 to 40. 

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