Poly Trimethylene Carbonate PTMC

High molecular weight poly(trimethylene carbonate) PTMC (Mn 300 k g/mol, Mw/Mn 1.46), synthesized, purified, and characterized as described in reference [72] is dissolved in chloroform (3 mg/mL). Thin films are prepared by spin-coating these solutions on cleaned Si wafers at 3,000 rpm (film thickness obtained 25 50 nm). Film thicknesses can be determined by AFM imaging using the scratch method described in Chap. 2 (see also above, hands-on example 47). The enzymatic reaction takes place in situ in the liquid cells filled with lipase solutions (lipase from Thermomyces lanuginosus (EC3.1.1.3, minimum 50,000 units/g purchased from Sigma, U.S.A.) at 37°C for 30 s, 1 min, and 2 min, respectively. 

A degradable triblock copolymer, poly(trimethylene carbonat e)-block-poly[poly(ethylene glycol)-co-cyclic acetal]-Mock-poly(trimethylene carbonate) (PTMC-fe-PECA-b-PTMC), was obtained via chemo-enzymatic approach [118]. The synthesized triblock copolymer consists of a degradable hydrophilic PECA (a,co-glycol synthesized chemically) and an amorphous hydrophobic PTMC (lipase CA-catalyzed polymerization of TMC). 

Chemical structure of poly(trimethylene carbonate) (PTMC). 

Degradable polymers such as polylactide (PLA), polyglycolide (PGA), poly(e-caprolactone) (PCL), poly(trimethylene carbonate) (PTMC) and poly (para-dioxanone) (PDO) have been widely investigated, and approved by FDA for use in the biomedical field (Middleton and Tipton, 2000). Table 4.1 presents the stmctures and thermal properties of these polymers. 

Scheme 4.1 Synthesis of poly(trimethylene carbonate) (PTMC) by reaction of carbon dioxide with oxetane. TMC, trimethylene carbonate.

Figure 4.6 Contact angle changes of poly(trimethylene carbonate) (PTMC) during immersion in phosphate buffer containing 0.2 mg/mL lipase CA, and of P(TMC-co-GA) 84/16 (PTGA) during immersion in phosphate buffer containing 0.2 mg/mL lipase HP. CA, Candida antarctica-, HP, Hog pancreas.

The physical and mechanical properties of polyanhydrides can be altered by minor modifications. Biodegradable polymer blends of polyanhydrides and polyesters have been investigated as dmg carriers (Leong et al., 1984). A polymeric blend of poly (trimethylene carbonate) (PTMC) with poly(adipic anhydride) (PAA) and the matrix of PTMC—PAA blend was found to be biocompatible in vitro and in vivo experiments as well as a promising candidate for controlled drug delivery erosion with tuneable erosion rate achieved by varying the proportion of PTMC and PAA (Edlund and... 

PLA Blended with Poly(propylene carbonate) (PPC) and Poly(trimethylene carbonate) (PTMC)... 

The matrices of polymers such as poly(vinyl pyrrolidone) (PVP), polysul-fone, poly(trimethylene carbonate) (PTMC), triethylene glycol diacetate-butyl propenoate copolymer [28], and cellulose [29] are different from the mentioned polymers in Sections from 11.1 to 11.5. For example, when porous polysulfone is used as the polymer carrier, the ionic conductivity (3.93 x 10 S/cm at room temperature) and mechanical performance are greatly improved after adding plasticizers. When organic electrolyte is added to PTMC, the uptake ability is greatly improved because its structure is similar to that of the organic electrolyte. Methylcellulose (MC) is prepared easily as a porous polymer membrane, as illustrated in Figure 11.34. It can absorb liquid electrolyte to become a gel polymer electrolyte whose ionic conductivity is 0.2 mS/cm and lithium-ion transference number is 0.29. These results can compare with the commercial separator [29]. 

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