Molecular weight polymer from methylene

General methods for the synthesis of poly(amide-anhydrides) and poly(amide-esters) based on naturally occurring amino acids were described (Domb et at, 1990). The polymers were synthesized from dicarboxylic acids prepared by amidation of the amino group of an amino acid with a cyclic anhydride, or by the amide coupling of two amino acids with a diacid chloride. Low molecular weight polymers from methylene bis(p-carboxybenzamide) were symthesized by melt condensation (Hartmann et al, 1989). A series of amido containing polyanhydrides based on p-aminobenzoic acid were sy nthesized by melt condensation. The polymers melted at 58 to 177°C and had a molecular weight of 2500 to 12400. 

Allyl alcohol, CH2=CH—CH2OH (2-propen-l-ol) [107-18-6] is the simplest unsaturated alcohol. One hydrogen atom can easily be abstracted from the aHyhc methylene (—CH2—) to form a radical. Since the radical is stabilized by resonance with the C=C double bond, it is very difficult to get high molecular weight polymers by radical polymerization. In spite of the fact that aHyl alcohol has been produced commercially for some years (1), it has not found use as a monomer in large volumes as have other vinyl monomers. 

Differential solubility was used to check for the presence of block copolymer. First, the higher molecular weight polymer was isolated from the reaction mixture by precipitation in isopropyl alcohol. Neither poly(hexylmethylsilane) nor poly(phenylmethylsilane) are soluble in this alcohol. Poly(hexylmethylsilane) is soluble in hexane, but poly(phenyl-methylsilane) is not. The precipitated polymer was then dissolved in methylene dichloride and added to hexane. The polymer that precipitated was recovered by filtration the rest was recovered by evaporation of the solution. 

Nagata and Hizakae [153] reported preparation of a series of photocross-linkable biodegradable polymers by condensation of dichlorides of 4,4 -(adipoyldioxy)dicinnamic acid and alkane diols of various methylene lengths. They also used various poly(ethylene glycols) with molecular weights ranging from 200 to 8,300. 

A series of low-molecular-weight resins from natural products or industrial side products is known as cumarone-indene-like resins, since these resins have similar physical properties to the actual cumarone-indene resins. For example, cyclopentadiene from the petroleum process dimerizes easily to what is known as dicyclopentadiene (lUPAC 4,7-methylene-4,7,8,9-tetrahydroindene). Dicyclopentadiene cationically polymerizes to polymers with different monomeric units. The commercially available polymers soften at 100-120°C and become insoluble as surface films on further heating. 

Methylene dichloride is a particularly good solvent for PP extraction because of its high volatility. In addition to additives, most solvents also extract some low molecular weight polymer with subsequent contamination of the extract. To overcome this, Slonaker and Sievers [2] have described a procedure for obtaining polymer-free additive extracts from PE based on low temperature extraction with n-hexane at 0 C. This procedure is also applicable to PP and PS. 

After a series of mechanical horror stories, attention was turned from transesterification to direct phosgenation. High molecular weight polymer was produced by passing phosgene into a stirred solution of bisphenol-A in a mixed methylene chloride/pyridine solvent. Excess pyridine and by-product pyridine hydrochloride was removed by water/acid washing. The polymer was recovered by addition of an anti-solvent such as alcohol or aliphatic hydrocarbon. This general process provided initial development quantities of polymer. 

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