Effect of silica resources on the biodegradation behavior of poly (lactic acid) and chemical crosslinked poly (lactic acid) composites

Biodegradation tests of PLA and chemically crosslinked PLA (CrPLA) filled with two different types of SiO2 (RSiO2 and CSiO2) that were surface-treated with stearic acid were studied using a CO2 detection technique. Triallyl isocyanurate (TAIC) in the presence of dicumyl peroxide (DCP) was selected as a chemical crosslinking agent. The incorporation of SiO2 fillers altered the peak of the TAIC-carbonyl functional group at 1685 cm−1 by interfering with the chemical crosslinking reaction, which affected the crystallinity and melting behaviors of SiO2/CrPLA composites, as observed by DSC thermograms. The FTIR spectra of surface-treated RSiO2 and CSiO2 showed that RSiO2 was significantly changed, with the silanol vibration peak observed at 960 cm−1, which indicated a strong reaction with stearic acid. The addition of SiO2 resulted in more water absorption with extensive surface erosion, and eventually, faster biodegradation and faster rates of composited samples were discovered. The higher content of loaded SiO2 was also found to improve the amount of water absorption, which accelerated biodegradation. However, CSiO2 is more effective at accelerating biodegradation than RSiO2 is for PLA and CrPLA because of its greater hydrophilicity.