Hydrolytic degradation of biodegradable polyesters under simulated environmental conditions

Abstract

In this study, the durability of poly(butylene succinate) (PBS), poly(butylene adipate-co-terephthalate) (PBAT), and PBS/ PBAT blend was assessed by exposure to 50 C and 90% relative humidity for a duration of up to 30 days. Due to the easy hydrolysis of esters, the mechanical properties of PBS and PBAT were significantly affected with increasing conditioning time. The PBS, PBAT, and PBS/PBAT showed an increase in modulus as well as a decrease in tensile strength and elongation at break with increased exposure time. Furthermore, the impact strength of PBAT remains unaffected up to 30 days of exposure. However, it was clearly observed that the fracture mode of PBS/PBAT changed from ductile to brittle after being exposed to high heat and humid conditions. This may be attributed to the hydrolysis products of PBS accelerating the degradation of PBAT in the PBS/PBAT blend. The differential scanning calorimetry results suggested that the crystallinity of the samples increased after being exposed to elevated temperature and humidity. This phenomenon was attributed to the induced crystallization from low molecular weight polymer chains that occurred during hydrolysis. Therefore, low molecular weight polymer chains are often favored to the crystallinity enhancement. The increase in crystallinity eventually increased the modulus of the conditioned samples. The enhanced crystallinity was further confirmed by polarizing optical microscopy analysis. Moreover, the hydrolysis of the polyesters was evaluated by scanning electron microscopy, rheology, and Fourier transform infrared spectroscopy analysis.

Enhancing the thermo‐oxidative stability of PLA through the use of hybrid organic–inorganic coatings

“…This process can induce the partial erosion of the amorphous phase and the consequent formation of more mobile segments, able to be included in the existing crystals. This increase in crystallinity as degradation proceeds has been found in other polyesters submitted to hydrolysis …”

Injection Molded Sustainable Biocomposites From Poly(butylene succinate) Bioplastic and Perennial Grass

“…The impact strength of neat PBS is around 28 J/m, which can be comparable to homopolypropylene. 26 The impact strength of MAH-g-PBS (64 J/m) is significantly higher compared to that of neat PBS. The observed impact strength improvement in the MAH-g-PBS sample is attributed to partial cross-linking, which occurred during MAH grafting on the PBS backbone in the presence of DCP free radical initiator.…”

Biodegradable compatibilized polymer blends for packaging applications: A literature review

“…PBAT is synthesized from 1,4‐butanediol, terephthalic acid, and adipic acid monomers by polycondensation reactions . PBAT demonstrates good flexibility with a melting and glass transition temperature of 120 and −17 °C, respectively . The PBAT has mechanical properties similar to that of low‐density polyethylene (LDPE), while the oxygen barrier property of the PBAT is 50% lower than LDPE .…”