Synthesis of high‐impact biodegradable multiblock copolymers comprising of poly(butylene succinate) and poly(1,2‐propylene succinate) with hexamethylene diisocyanate as chain extender

Abstract

Block copolymers demonstrate excellent thermal and mechanical properties superior to their corresponding random copolymers and homopolymers. However, it is difficult to synthesize block copolymers comprising of different polyester segments by copolycondensation due to the serious transesterification reaction. In this study, multiblock copolymers comprising of two different polyester segments, i.e. crystallizable poly(butylene succinate) (PBS) and amorphous poly(1,2-propylene succinate) (PPSu), were synthesized by chain-extension with hexamethylene diisocyanate (HDI). Amorphous PPSu segment was incorporated to improve the impact strength of PBS. The copolymers were characterized by GPC, laser light scattering (LLS), NMR, DSC, and mechanical testing. The results of 13 C NMR spectra suggest that multiblock copolymers with regular sequential structure have been successfully synthesized. The data of DSC and mechanical testing indicate that block copolymers possess excellent thermal and mechanical properties with satisfactory tensile strength and extraordinary impact strength achieving upto 1900% of pure PBS. The influence of PPSu ratio and chain length of both the segments on the thermal and mechanical properties was investigated. The incorporation of an amorphous soft segment PPSu imparts high-impact resistance to the copolymers without obviously decreasing the melting point (T m ). The favorable mechanical and thermal properties of the copolymers also depend on their regular sequential structure. At the same time, the introduction of amorphous PPSu segment enhances the enzymatic degradation rate of the multiblock copolymers.

High‐molecular‐weight poly(1,2‐propylene succinate): A soft biobased polyester applicable as an effective modifier of poly(l‐Lactide)

“…Wang et al . also prepared a PPS oligomer with M n = 2.4 kDa in a similar way and used it for making a PPS‐co‐PBS by chain‐extension with hexamethylene diisocyanate (HMDI) . Dong et al .…”

Synthesis of high molecular weight aromatic polyesters via integrated alternating ring‐opening copolymerization and chain extension methods

“…The chain extension strategy is an effective approach to obtain high M n PEs. Hexamethylene diisocyanate (HDI) is an excellent chain extender, since it interferes less with the chain structure and crystallization of the PEs . Also, the resultant urethane bonds are biodegradable due to the aliphatic nature of HDI.…”

Structure analysis and thermal degradation characteristics of bio-based poly(propylene succinate)s obtained by using different catalyst amounts

“…At the PPS-0.2 sample spectrum, other peaks are also visible in lower intensity which can indicate the end groups of oligomers. The little triple peak at 3.65 ppm named 'x' attributed to methylene protons from hydroxyl terminated ends (-CH 2 -OH) of polyester macromolecules [28]. The peak at 4.35 ppm named 'z' attributed to the triple peak corresponding to methylene protons (-CH 2 -O-) from glycol terminated ends group.…”