Preparation and Properties of Poly(l-lactide)-block-poly(trimethylenecarbonate) as Biodegradable Thermoplastic Elastomer

Abstract

ABSTRACT:Biodegradable ABA triblock copolymers of L-lactide and trimethylene carbonate with given compositions were prepared and chain-extended to produce high molecular weight polymer. The polymers were semicrystalline, and exhibited well microphase-segregated morphology with one crystalline poly(L-lactide) (PLLA) and the other soft and amorphous poly(trimethylene carbonate) (PTMC) block segments. The polymers could be cast into flexible and tough film, reversibly stretchable with elongation up to about 300%. This material may provide a novel thermoplastic elastomer possessing desirable properties including biodegradability, biocompatibility and good mechanical properties including two-phase morphology. Also a preliminary result on the hydrolytic degradation behavior was discussed.KEY WORDS Poly(L-lactide) (PLLA) / Poly(trimethylene carbonate) (PTMC) / Block Copolymer / Biodegradable / Thermoplastic Elastomer /

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

“…It is evident that the covalently bonded amorphous chain segments greatly hinder the crystallization process of PLA homocrystals. A similar decrease in crystallinity with respect to the pre-polymer has been measured in our recent work for PLA-poly(tetrahydrofuran) multiblock copolymers [40], and for other PLA-based multiblock obtained by chain-extension with diisocyanate [19,23,33]. It must be mentioned that the decrease in crystallization kinetics can also be partially ascribed to the higher molecular weight of the multiblock derivative.…”

“…Despite the fact that this second approach leads to a rigorously controlled length of the different blocks in the multiblock copolymer, a more complex synthetic procedure is required. Soft blocks employed so far to build this class of multiblocks copolymers based on PLA are not derived from bio-renewable feedstocks, although some of them are bio-degradable [19,[23][24][25]30,33,35,36,42].…”

Triblock Copolymers Based on 1,3‐Trimethylene Carbonate and Lactide as Biodegradable Thermoplastic Elastomers

“…amorphous poly(DLLA) and semi-crystalline poly(LLA) or poly(DLA) with different physical and degradation properties, have been used as hard blocks in TPEs for medical applications. For instance, poly(LLA-TMC-LLA) triblock copolymers were chain extended to form completely degradable multiblock copolymers, [22][23][24] and partially degradable TPEs were prepared from poly(DLLA-isoprene-DLLA) triblock copolymers. [25,26] Blends of poly(LLA) and poly(DLA) form a stereo-complex with a melting point of approximately 230 8C.…”

Comparison of Sm complexes with Sn compounds for syntheses of copolymers composed of lactide and cyclic carbonates and their biodegradabilities

“…Thus, physical properties should be improved by copolymerizations of lactide with other monomers in order to generate softer and tougher materials. For this purpose, cyclic carbonates are of great interest as comonomers because of the soft property of the resulting copolymers [11][12][13][14][15][16][17]. In our previous works, we studied synthesis and biodegradabilities of random copolymers of L-LA with (R)-, (S)-, or rac -1-methyltrimethylene carbonate polymerized by using a samarium initiator (C 5 Me 5 ) 2 SmMe(THF) (Sm1) [18][19][20][21][22][23].…”

“…We have also reported random, diblock, and triblock copolymers of L-and D,L-LA with achiral cyclic carbonates such as trimethylene carbonate (TMC) and 2,2-dimethyltrimethylene carbonate (DTC) polymerized by using Sm1 or a bifunctional initiator (C 5 Me 5 ) 2 Sm(PhC=C=C= CPh)Sm(C 5 Me 5 ) 2 (Sm2) [24,25]. On the other hand, high molecular weight poly(LA)s were prepared using tin compounds such as Sn(2-ethylhexanoate) 2 and Bu 2 Sn(OR) 2 [5,15,[26][27][28][29][30][31]. This paper describes the comparison of the activities between Sm complexes and Sn compounds for random and diblock copolymerization of LA and cyclic carbonates together with the triblock copolymerization, and their biodegradabilities with a compost and with proteinase K.…”