Siloxane, dimethyl-, copolymer with

Smith, S. D., J. M. DeSimone, G. York, D. W. Dwight, G. L. Wilkes, and J. E. McGrath. 1987. Blends of poly(methyl methacrylate)-poly(dimethyl siloxane) graft copolymers with poly(methyl methacrylate) and poly(vinyl chloride). Paper presented at the ACS Meeting, New Orleans, LA, August. 

Lu, Z.-H., Krause, S., and Iskander, M., Properties of low molecular weight block copolymers 3. Mixtures of styrene-dimethyl siloxane diblock copolymers with polystyrene. Macromolecules, 15, 367-370 (1982). 

Poly(dimethyl siloxanc) with vinyl or hydrosilanc (Si-H) chain ends have been converted to ATRP initiator ends e.g. Scheme 9.62) by hydrosilylalion, Bis-functional dimethyl siloxane polymers prepared in this way were used in polymerizations of S, MA, tsobornyl acrylate and BA to form ABA triblock copolymers. 

THERMAL CHARACTERIZATION OF POLY (DIMETHYL SILOXANE) COPOLYMERS WITH POLY (HYDROXY STYRENE) AND 2-METHYL... 

In addition to providing fully alkyl/aryl-substituted polyphosphazenes, the versatility of the process in Figure 2 has allowed the preparation of various functionalized polymers and copolymers. Thus the monomer (10) can be derivatized via deprotonation—substitution, when aP-methyl (or P—CH2—) group is present, to provide new phosphoranimines some of which, in turn, serve as precursors to new polymers (64). In the same vein, polymers containing a P—CH3 group, for example, poly(methylphenylphosphazene), can also be derivatized by deprotonation—substitution reactions without chain scission. This has produced a number of functionalized polymers (64,71—73), including water-soluble carboxylate salts (11), as well as graft copolymers with styrene (74) and with dimethyl siloxane (12) (75). 

Fig. 18. Density vs. PDMS content for a homopolyimide and the polyimide/poly(dimethyl-siloxane) perfectly alternating block copolymers with the 11,000 g/mol polyimide segments...

Thermal decomposition of poly(alkylsiloxane) copolymers is similar to that of poly(dimethylsiloxane), the main compound generated from the siloxane moiety being cyclic siloxanes. The results for a Py-GC/MS analysis of a sample of poly(dimethyl-siloxane-co-methylphenylsiloxane) with phenyl/methyl mole ration 1/1 are shown in Figure 16.1.2. The polymer idealized formula is [-Si(CH3)20-]x [-Si(CH3)(C6H5)0-]y where x = y. The pyrolysis was done at 600° C in He with the analysis done in the same conditions as for other examples previously discussed (see Table 4.2.2). The peak identification for the chromatogram was done using MS spectral library searches only and it is given in Table 16.1.4. 

Chitin is known to be biodegradable, biocompatible, and nontoxic. It is used in dmg delivery and bio medical applications. It also used in the purification of water especially for the absorption of toxic dyes. Chitin has limited solubility in solvents but chitosan is readily soluble in acidic aqueous solutions and has more tendency to be chemically modified. Chitosan can readily be spun into fibers, cast into films, or precipitated in a variety of micromorphologies from acidic solutions. Min and Kim have reported on the adsorption of acid dyes from wastewater using composites of PAN/chitosan [52]. Shin et al. has reported on copolymers composed of PVA and poly dimethyl siloxanes cross-linked with chitosan to prepare semi IPN hydrogels for application as biomedical materials... 

Water can be removed from methanol by a membrane of polyvinyl alcohol cross-linked with polyacrylic acid, with a separation factor of 465.204 A polymeric hydrazone of 2,6-pyridinedialdehyde has been used to dehydrate azeotropes of water with n- and /-propyl alcohol, s- and tort butyl alcohol, and tetrahydrofuran.205 The Clostridium acetobutylicum which is used to produce 1-butanol, is inhibited by it. Pervaporation through a poly(dimethyl-siloxane) membrane filled with cyclodextrins, zeolites, or oleyl alcohol kept the concentration in the broth lower than 1% and removed the inhibition.206 Acetic acid can be dehydrated with separation factors of 807 for poly(4-methyl-l-pentene) grafted with 4-vinylpyridine,207 150 for polyvinyl alcohol cross-linked with glutaraldehyde,208 more than 1300 for a doped polyaniline film (4.1 g/m2h),209 125 for a nylon-polyacrylic acid membrane (5400 g/m2h), and 72 for a polysulfone.210 Pyridine can be dehydrated with a membrane of a copolymer of acrylonitrile and 4-styrenesulfonic acid to give more than 99% pyridine.211 A hydrophobic silicone rubber membrane removes acetone selectively from water. A hydrophilic cross-linked polyvinyl alcohol membrane removes water selectively from acetone. Both are more selective than distillation.212... 

Poly(Dimethyl Siloxane) Sihcone Rubber, Usually Copolymer with Vinyl groups (VMQ) Poly(Dimethyl Siloxane) Copolymer with Phenyl-Bearing Siloxane and Vinyl Groups (PVMQ) Room Temperature Vulcanizing Silicone Polysulfide (ET and EOT) Polyurethane (AU and EU)... 

A rubbery/crystalline combination consisting of poly(dimethyl siloxane)/poly(diphenyl siloxane). The crystalline, high-melting diphenyl siloxane blocks alternate with rubbery dimethyl siloxane blocks, and the resulting copolymer behaves like a thermoplastic elastomer. 

Polyamide-6 (nylon 6) can form block copolymers with rubber [419] and with poly(dimethyl-siloxane) [420]. In the latter case, the polysiloxane forms first by living polymerization and is terminated by an acylated caprolactam. The caprolactam portion of the molecule is then polymerized with the aid of lithium caprolactamate ... 

Silicone PSAs are blends or reaction products of the combination of a poly-organosiloxane, such as poly(dimethyl siloxane) or its copolymers with diphenyl-siloxane or methylphenyl siloxane, with a polysiloxane resin, which is largely inorganic. Pendant vinyl groups may also be incorporated into silicone PSAs,... 

Silphenylene-Siloxane Copolymers.—The thermal properties vctsus structure for poly(tetramethyl-p-silphenylensesiloxane) and (tetramethyl-p-silphenylene/di-methylsiloxane) block copolymers have been compared. The homopolymer has a m.p. of 160°C, heat of fusion of 54.4 J/g and Tg of —20°C. The Tg of the copolymer varies monotonically with inojeased dimethylsiloxane content, from — 20 to —123 °C. Data have been reported on the crystallization kinetics and morphology of blends of fractionated poly(tetramethyl-p-silphenylenesiloxanes). The chemical degradation of poly(tetramethyl-/ -silphenylenesiloxane/dimethyl-siloxane) block copolymers by HF has been reported. In 48% HF at 30 °C, preferential attack occurs at the Si—O bond, particularly those of the MejSi—O non-crystalline components, in copolymers containing 15, 35, and 52% poly-dimethylsiloxane. - Further data have been reported on the crystal structure and fold conformation of poly(tetramethyl-/>-silphenylenesiloxane)s, obtained from X-ray diffraction studies. ... 

Polyurethane networks were prepared by crosslinking ethylene oxide/propylene oxide block copolymers, ethylene oxide/propylene oxide/dimethyl siloxane graft copolymers, and poly(ethylene oxide) with various isocyanates (179). Complexation with lithium perchlorate led to network shrinkage and increases in Tg. The data suggested regular chain partitioning by the salt. 

YAN Yang, J., Wegner, G., and Koningsveld, R., Phase behavior of ethylene oxide-dimethyl-siloxane PEO-PDMS-PEO triblock copolymers with water. Colloid Polym. Sci., 270, 1080,... 

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