Alkylene monomer synthesis

Alkylene Monomer Synthesis. Ethylene monomer 5 was prepared by the hydrosilation of vinyltriethoxysilane with triethoxysilane in the presence of chloroplatinic acid. Propylene monomer 6 was synthesized by hydrosilating allyltriethoxysilane. The remaining monomers 7-9 were prepared by hydrosilating the... 

Polycarbonate synthesis by lipase-catalyzed polycondensation was demonstrated. Activated dicarbonate, 1,3-propanediol divinyl dicarbonate, was used as the monomer for enzymatic synthesis of polycarbonates.222 Lipase CA-catalyzed polymerization with a,co-alkylene glycols produced the polycarbonates with Mw up to 8.5 x 103. Aromatic polycarbonates with DP larger than 20 were enzymatically obtained from the activated dicarbonate and xylylene glycols in bulk.211... 

Culvenor, Davies, and Pausacker extended the alkylene oxide-thiourea, thiocyanate, or thiocarbamide synthesis to prepare the higher alkylene sulfide monomers [53],... 

As mesogenic groups, 4 -trifluoromethoxy-azobenzene units are used and linked to the methacrylate main chain by alkylene spacer, where the number n of the spacer groups was varied from 2 to 6. The chemical structure of the repeating unit of the polymers PM (n=2-6) is given in Figure 1. Details of the synthesis of the monomer, the condition for the radical polymerization, and the determination of the molecular masses were reported elsewhere 19,20). The phase transition temperatures of the polymers were... 

Synthesis involves the formation of apoly(alkylene carbonate) prepolymer formed from intermediates of organic carbonate moieties by reaction of a diol and organic carbonate monomer at elevated temperatures in the presence of a catalyst such as stannous octoate. Diols include 1,6-hexanediol, 1,4-butanediol and 1,8-octanediol, wi hile carbonates include diphenyl carbonate and dibutyl carbonate. p-Dioxanone is then added to form the poly(p-dioxanone-co-alkylene carbonate) copolymer. 

Fig. 3 Synthesis processes of bridged alkylenes polysilsesquioxanes from various kind of hydrocarbon monomers and reactive silicate species...

Broer DJ, Mol GN, Challa G (1991) In-situ photopolymerization of oriented liquid-crystalline acrylates, 5. Influence of the alkylene spacer on the properties of the mesogenic monomers and the formation and properties of oriented polymer networks. Makromol Chem 192 59-74 Buruiana T, Melinte V, Costin G, Buruiana EC (2011) Synthesis and properties of liquid crystalline urethane methacrylates for dental composite applications. J Polym Sci A Polym Chem 49 2615-2626... 

Polymerizations of unsaturated monomers, such as olefins, vinyl monomers, or acetylenes, exclusively proceed as KC reaction sequences. With exception of crystalline polyethylene, the resulting polymers are thermodynamically unstable, because the corresponding cyclohexanes or benzenes are more stable, but equilibration catalysts do not exist. As soon as polymer backbones include heteroatoms, equilibration reactions become possible, and many polymers may be prepared by KC and by TC polymerizations. An interesting case is synthesis and polymerization of oxiranes. Their synthesis from )S-bromoalcohols and their polymerization via anionic or coordination insertion catalysts represent KC reactions. Yet, heating of oxiranes or poly(alkylene oxides)s with strong protic acids yields the thermodynamically more stable 1,4-dioxanes. 

---