2,2-dimethyltrimethylene carbonate

The coordination polymerisation of cyclic carbonates with a six-membered ring in the molecule, such as trimethylene carbonate (l,3-dioxan-2-one) and 2,2-dimethyltrimethylene carbonate (5,5-dimethyl-l,3-dioxan-2-one) [148-150], carried out in the presence of metal carboxylates e.g. zinc stearate, tin-based catalysts such as the di(w-butyl)stannic diiodide-triphenylphosphine system [151] or porphinatoaluminium compounds such as (tpp)AlOR [149] is not accompanied with decarboxylation and yields the respective polycarbonates (Table 9.2). The ring cleavage during the polymerisation of trimethylene carbonate and 2,2-dimethyltrimethylene carbonate in the presence of the above catalysts has been found [148,149,151] to occur at the C(0)-0 bond, resulting... 

The dual function of the precatalysts 4 opened the way to well-controlled block polymerization of ethylene and MMA (eq. (5)) [89, 90]. Homopolymerization of ethylene (Mn = 10000) and subsequent copolymerization with MAA (Mn 20000) yielded the desired linear AB block copolymers. Mono and bis(alkyl/silyl)-substituted flyover metallocene hydride complexes of type 8 gave the first well-controlled block copoymerization of higher a-olefins with polar monomers such as MMA or CL [91]. In contast to the rapid formation of polyethylene [92], the polymerization of 1-pentene and 1-hexene proceeded rather slowly. For example, AB block copolymers featuring poly( 1-pentene) blocks (M 14000, PDI = 1.41) and polar PMMA blocks (M 34000, PDI = 1.77) were obtained. Due to the bis-initiating action of samarocene(II) complexes (Scheme 4), type 13-15 precatalysts are capable of producing ABA block copolymers of type poly(MMA-co-ethylene-co-MMA), poly(CL-co-ethylene-co-CL), and poly(DTC-co-ethylene-co-DTC DTC = 2,2-dimethyltrimethylene carbonate) [90]. 

Sebacic anhydride 2,2-Dimethyltrimethylene carbonate Tin-Depression Semicrystalline Wang et al. (2002a)... 

Dobrzynski, P., Kasperczyk, J., 2006a. Synthesis of biodegradable copolymers with low-toxicity zirconium compounds. IV. Copolymerization of glycolide with trimethylene carbonate and 2,2-dimethyltrimethylene carbonate microstructure analysis of copolymer chains by high-resolution nuclear magnetic resonance spectroscopy. Journal of Polymer Science Part A Polymer Chemistry 44, 98—114. 

Kricheldorf, H.R., Dunsing, R., Albet, A.S.i, 1987. Polylactones 12. cationic polymerization of 2,2-dimethyltrimethylene carbonate. Makromolekulare Chemie 188, 2453-2466. 

Kuhling, S., Keul, H., Hocker, H., 1990. Polymers from 2-allyloxymethyl-2-ethyltrimethylene carbonate and copolymers with 2,2-dimethyltrimethylene carbonate obtained by anionic ring-opening polyrmerization. Makromolekulare Chemie 191, 1611—1622. 

Yu, X., Zhuo, R., Feng, J., Liao, J., 2004. Enzymatic ring-opening polymerization of 2,2-dimethyltrimethylene carbonate catalyzed by PPL immobibzed on silica nanoparticles. European Polymer Journal 40, 2445—2450. 

Zhu, W., Ling, J., Xu, H., Shen, Z., 2005. Copolymerization of trimethylene carbonate and 2,2-dimethyltrimethylene carbonate by rare earth calixarene complexes. Polymer 46, 8379-8385. 

Kummerl5we and Kammer reported observations on the form of the crystalline structure in blends of PCL (M =40,000) with a diblock copolymer of PCL (M = 20,000) andpoly(2,2-dimethyltrimethylene carbonate) (PDTC) 30 (M =20,000) both components of the block copolymer are crystallisable. 

Scheme 12.1 Ring-opening polymerization of 2,2-dimethyltrimethylene carbonate (a model monomer for cyclic carbonates) with nucleophilic initiators an equilibrium polymerization.

CycHc carbonates such as 2,2-dimethyltrimethylene carbonate (DTC) are polymerized either anionicaUy or by insertion in a ring-opening fashion with a variety of initiating systems based on alkah metals (II, Na, K) [11], earth-alkali metals (Mg)... 

Scheme 12.3 Initiation, side reactions and site transformation in ring-opening polymerization of 2,2-dimethyltrimethylene carbonate initiated by polystyrene lithium.

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