Fast Crystallization and Toughening of Poly(L-lactic acid) by Incorporating with Poly(ethylene glycol) as a Middle Block Chain

Improvement in Mechanical Properties and Heat Resistance of PLLA-b-PEG-b-PLLA by Melt Blending with PDLA-b-PEG-b-PDLA for Potential Use as High-Performance Bioplastics

“…The DSC results are summarized in Table 2. The T g of the blends were in range 27-29 ∘ C. The flexible PEG middle-blocks acted as plasticizers to decrease the T g of the PLA end-blocks [12,13]. The stereocomplexation of PLLA and PDLA endblocks did not affect glass-transition behaviors of the blends.…”

“…All the films had a yield point indicating the films were flexible except the 50/50 blend film. The flexible PEG middle-blocks enhanced the plasticizing effect of the polylactide end-blocks [12,13]. The stress at yield of films increased with the PDLA-PEG-PDLA ratio.…”

“…High molecular-weight PLLA-b-poly(ethylene glycol)-b-PLLA (PLLA-PEG-PLLA) were more flexible than the PLLA because of flexible PEG middle-blocks enhanced plasticizing 2 Advances in Polymer Technology effect that decreased the T g of the PLLA end-blocks [12,13]. However the heat-resistance of PLLA-PEG-PLLA was still low.…”

Nanostructured poly(l-lactic acid)–poly(ethylene glycol)–poly(l-lactic acid) triblock copolymers and their CO2/O2permselectivity

“…The second peak was a small shoulder at 2860 cm À1 and was due to vibrations of CH 2 in amorphous regions of PEG. 32 For the copolymers, on one hand, the stretching band assigned to crystalline PEG at 2886 cm À1 was almost eliminated in PLGL55G20. On the other hand, the intensity of the band for amorphous PEG at 2860 cm À1 increased, implying that most of the PEG blocks exist in an amorphous state in all of the copolymers.…”

“…On the other hand, the presence of large exible PEG chains can improve signicantly the mobility of polymer chains and decrease the glass transition temperature (T g ) of the copolymers. 32 A decrease of the T g (Table S1 †), and an increase of mobility leads to an increase of the free volume of the copolymers. Thus, the gas penetrates the copolymer lm more easier than pure PLLA under the same conditions.…”