Mechanical, thermal and rheological properties and morphology of poly (lactic acid)/poly (propylene carbonate) blends prepared by vane extruder

The in situ formation of poly(lactic acid)‐b‐poly(propylene carbonate) (PLA‐b‐PPC) block copolymers were carried out by the reaction between PLA and PPC in the presence of tetrabutyl titanate via transesterification. Molecular weight measurements and 13C nuclear magnetic resonance spectroscopy revealed that PLA‐b‐PPC block copolymers with higher molecular weight were obtained by controlling the reactivity point ratio between PLA chains and PPC chains in PLA/PPC reaction system. The sample with a composition of PLA:PPC = 40:60 (wt %) and a catalyst amount of 0.5 wt % had a more proportionable reactivity point ratio between PLA chains and PPC chains compared with other samples, resulting in a most conspicuous transesterification and inconspicuous chain scission reaction. Therefore, its high molecular weight fraction (Mw > 40.0 × 104) increased 80%. The formation of macromolecular PLA‐b‐PPC copolymer could strengthen the entanglement between PLA and PPC molecular chains, which resulted in an increased viscosity of blends at low shear rate. In addition, the elongation at break of sample with a composition of PLA:PPC = 40:60 (wt %) and a catalyst amount of 0.5 wt % was nearly as twice as which without catalyst because of the improving miscibility of PLA domains and PPC matrix by the compatibilization of PLA‐b‐PPC copolymer. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46009.

Section: Resultssupporting

confidence: 93%

Compatibilization of the poly(lactic acid)/poly(propylene carbonate) blends through in situ formation of poly(lactic acid)‐b‐poly(propylene carbonate) copolymer

Wang

Zhang

Liu

et al. 2017

“…In this study, we investigated the rheological behavior of the LLDPE/PET/LLDPE‐ g ‐MAH blends in response to shear frequency via dynamic rheological technique, which can illustrate the compatibility between LLDPE and PET phase. The complex viscosity (η*) varies with frequency curves of the LLDPE/PET/LLDPE‐ g ‐MAH blends with various matrix weight ratio are shown in Figure .…”

Section: Resultsmentioning

confidence: 99%

“…The compression molding machine is equipped with water cooling system, the molded sheets were cooled in the mold by water. The dumbbell‐shaped specimens and rectangular specimens for tensile and impact testing were cut to meet the requirements (width × thickness × length of parallel part × total length: 4 × 1 × 25 × 75 mm and length × width × thickness: 80 × 10 × 4 mm), respectively . The specimens for rheology testing were cut into disks with a diameter of 25 mm and thickness of 1 mm …”

Section: Methodsmentioning

confidence: 99%

“…The rheology behavior of the neat PET, neat LLDPE, and the LLDPE/PET/LLDPE‐ g ‐MAH blends were investigated by using a rotational rheometer (MCR 302, Paar, Anton). All tests were implemented at a temperature of 260 °C with a scanning frequency from 0.0628 to 628 rad/s, and the strain amplitude was kept at 5% …”

Section: Methodsmentioning

confidence: 99%

“…27 The specimens for rheology testing were cut into disks with a diameter of 25 mm and thickness of 1 mm. 27…”

Section: Sample Preparationmentioning

confidence: 99%

See 2 more Smart Citations

Linear low‐density polyethylene/poly(ethylene terephthalate) blends compatibilization prepared by an eccentric rotor extruder: A morphology, mechanical, thermal, and rheological study

Xue

Jia

et al. 2018

In this study, various poly(ethylene terephthalate) (PET) and linear low‐density polyethylene (LLDPE) with maleic anhydride‐grafted LLDPE (LLDPE‐g‐MAH) compatibilizer were melt blended under an elongational flow. A novel extrusion device, eccentric rotor extruder (ERE), was developed to supply such flow during the process. Including morphology, mechanical properties, melting behavior, and rheological behavior were studied. The morphological study showed that the compatibility between LLDPE and PET was greatly improved with LLDPE loading up to 80 wt %. Mechanical tests indicated that LLDPE could toughen PET to some extent. Moreover, a comparison of samples prepared between ERE and conventional extruder was made and demonstrated the sample prepared by ERE can exhibit better mechanical properties. Differential scanning calorimetry results revealed that PET can promote the crystallinity of LLDPE. Rheological behavior indicated that the complex viscosity of the blends exhibited strong shear thinning phenomenon with increasing LLDPE content, particularly in high‐frequency range blend with the LLDPE weight ratio of 80 wt % was more sensitivity to shear rate than neat LLDPE. The G′‐G″ curves of the blends also revealed that the microstructure of the blends changed significantly with the addition of LLDPE which was consistent with the scanning electron micrographs that PET particles became smaller and distributed more uniform with increasing LLDPE content. Furthermore, the blends showed similar stress relaxation mechanism with adding LLDPE content from 60 to 100 wt %. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46489.

Structure and improved properties of PPC/PBAT blends via controlling phase morphology based on melt viscosity

Jiang

Wang

Zhang

et al. 2020

Poly(propylene carbonate) (PPC)/poly(butylenes adipate‐co‐terephthalate) (PBAT) blends with various composition ratios were prepared via melt mixing using a twin‐screw extruder. The effect of melt viscosities of polymers on mechanical behavior, interfacial interaction, thermal properties, rheological responses, and phase morphology was investigated. Results showed that the phase morphology and properties of PPC/PBAT blends were affected by the composition of the blends and the melt viscosities of the two polymers. Results of tensile tests, FTIR, and dynamic rheological measurement of PBAT‐rich blends exhibited a better mechanical properties, intermolecular interactions, and compatibility when compared with PPC‐rich blends due to the differences of their melt viscosities. Incorporating of PBAT effectively improved the Tg of PPC and the thermal stability of the blends. The Tc of PPC/PBAT blends markedly increased from 37.5 to 66.8 °C with addition of only 10 wt% PPC, indicating an enhanced crystallization ability of PBAT. The improvement of Tc was helpful for blown film extrusion. SEM microphotographs showed that the size of the dispersed phase particles is much smaller and the distribution is more uniform for PBAT‐rich blends, compared with that in PPC‐rich blends. The processing stability of blown film extrusion was improved by blending PPC with PBAT. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48924.