Preparation of Chain‐Extended Poly(hexamethylene carbonate)s and their Block Copolymerization with Poly‐L‐lactide to Synthesize Partly Biobased Thermoplastic Elastomers

Abstract

An oligomer of poly(hexamethylene carbonate) (PHMC) that is synthesized by ester‐exchanging polycondensation of ethylene carbonate and 1,6‐hexanediol is chain‐extended by using diphenyl carbonate as chain extender. The resultant PHMC, dihydroxyl‐terminated, is then subjected to tin‐catalyzed ring‐opening polymerization of L‐lactide to prepare ABA tri‐block copolymers consisting of poly‐L‐lactide (PLLA: A) and PHMC (B), which retain significantly high molecular weights even at increased contents of PHMC. Polymer films of these block copolymers exhibit high elongation, reaching 700% at a high PHMC content. It is therefore suggested that the present block copolymer system can be a novel thermoplastic elastomer, which is partly bio‐based.

Synthesis and properties of stereo mixtures of enantiomeric block copolymers of polylactide and aliphatic polycarbonate

“…Figure shows the plots of crystallinity ( X ) as a function of APC content (soft block ratio) for the stereo mixtures and their corresponding single copolymers. The data for the latter are those previously reported . Although the APC contents are slightly different between the stereo mixtures and the single block copolymers, it is clear that the crystallinity is almost inversely proportional to the content of soft blocks.…”

“…Both PLLA‐PHMC‐PLLA and PLLA‐PHPC‐PLLA triblock copolymers were synthesized by tin‐catalyzed ROP of l ‐lactide in the presence of PHMC and PHPC diols as the initiators, as reported previously . The enantiomeric block copolymers PDLA‐PHMC‐PDLA and PDLA‐PHPC‐PDLA were also prepared likewise by using d ‐lactide as the monomer.…”

“…Having a telechelic structure comprising bis‐hydroxyl terminals, they are utilized as soft segments of polyurethane and other copolymers . Recently, we demonstrated that both PHMC and PHPC can be readily chain‐extended and used as macro‐initiators of the ring‐opening polymerization (ROP) of l ‐lactide to prepare ABA triblock copolymers (PLLA‐APC‐PLLA) consisting of PLLA (A) and APC (B: PHMC or PHPC) (Scheme ) . These block copolymers were shown to be useful as partly biobased thermoplastic elastomers.…”

Preparation of Chain-Extended Poly(hexamethylene/pentamethylene carbonate)s and Their Block Copolymerization with Poly-L-lactide into Partly Biobased Thermoplastic Elastomers

“…[14][15][16] With this nature in mind, we have demonstrated that PHMC diol can be used as a macroinitiator of the ring-opening polymerization (ROP) of L-lactide to prepare tri-block copolymers comprising poly-L-lactide (PLLA) and PHMC (PLLA-PHMC-PLLA) that have both biobased and CO2-originated characters. [17] Since PHMC is crystalline at ambient temperature, the properties of the PLLA-PHMC-PLLA copolymers may be significantly influenced by the temperature change. In the present study, therefore, we use amorphous PHPC diol as the macro-initiator to obtain similar PLLA-APC block copolymers, and for which the elastomeric properties are evaluated.…”

Fully bio-renewable multiblocks copolymers of poly(lactide) and commercial fatty acid-based polyesters polyols: Synthesis and characterization

“…The dihydroxyl terminated polymer is then used as a macro-initiator for the subsequent ring-opening polymerization of lactide. A variety of polymers can be used as soft block [16,17,21,27,31,38,41], provided that they have a suitably low glass transition temperature, and that they can be obtained with proper terminal functional groups. Recently, the research focused on the development of fully biobased PLA-containing triblocks copolymers, by employing biorenewable soft blocks, such as amorphous polyhydroxyalkanoates [18,26], polymethide [28] and polyesters derived from castor oil [44].…”