TY - JOUR
T1 - Crystallization and flame-retardant properties of polylactic acid composites with polyhedral octaphenyl silsesquioxane
AU - Jia, Lin
AU - Tong, Bin
AU - Li, Dinghua
AU - Zhang, Wenchao
AU - Yang, Rongjie
N1 - Publisher Copyright:
© 2018 John Wiley & Sons, Ltd.
PY - 2019/3
Y1 - 2019/3
N2 - To develop environmental-friendly and flame-retarded polymer composites, bio-based polylactic acid (PLA) was loaded with thermally stable polyhedral octaphenyl silsesquioxane (OPS). Pure PLA and PLA/OPS composites with the OPS of 1, 3, 5, and 10 wt% were prepared by extrusion and injection molding, respectively. The scanning electron microscopy (SEM), polarized optical microscope (POM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and thermal gravimetric analysis (TGA) were used to analyze the dispersion of the OPS in the PLA matrix and the effects of OPS on the crystallization and thermal stability properties of PLA/OPS composites, respectively. Limited oxygen index (LOI) and cone calorimeter (CONE) measurements were used to study flame retardancy of PLA and PLA/OPS composites. In order to study the flame-retardant mechanism, the char residues were investigated by SEM, Fourier transform infrared spectra (FTIR), and X-ray photoelectron spectroscopy (XPS). TGA-FTIR was used to analyze the gaseous products of their thermal decomposition. The results show that the OPS particles were submicron in the PLA and could increase the crystallization rate of PLA and form small-sized secondary α-form crystalline compared with the pure PLA spherulite. The PLA and OPS decomposed individually in the PLA/OPS composites by TGA. According to the LOI tests, the PLA with the OPS loading exhibited very small reduction of LOI. However, the CONE tests indicated that the OPS could improve the flame retardancy of the PLA by means of low peak heat release rate and average heat release rate. It was obtained that the degree and type of the PLA crystalline for the pure PLA and PLA/OPS affect their flame retardancy. In the max thermal decomposition stage of PLA and PLA/OPS, their gaseous products were similar; at high temperatures, the PLA/OPS produced simple and clear gaseous products of PLA with solid SiO 2 in the gas phase.
AB - To develop environmental-friendly and flame-retarded polymer composites, bio-based polylactic acid (PLA) was loaded with thermally stable polyhedral octaphenyl silsesquioxane (OPS). Pure PLA and PLA/OPS composites with the OPS of 1, 3, 5, and 10 wt% were prepared by extrusion and injection molding, respectively. The scanning electron microscopy (SEM), polarized optical microscope (POM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and thermal gravimetric analysis (TGA) were used to analyze the dispersion of the OPS in the PLA matrix and the effects of OPS on the crystallization and thermal stability properties of PLA/OPS composites, respectively. Limited oxygen index (LOI) and cone calorimeter (CONE) measurements were used to study flame retardancy of PLA and PLA/OPS composites. In order to study the flame-retardant mechanism, the char residues were investigated by SEM, Fourier transform infrared spectra (FTIR), and X-ray photoelectron spectroscopy (XPS). TGA-FTIR was used to analyze the gaseous products of their thermal decomposition. The results show that the OPS particles were submicron in the PLA and could increase the crystallization rate of PLA and form small-sized secondary α-form crystalline compared with the pure PLA spherulite. The PLA and OPS decomposed individually in the PLA/OPS composites by TGA. According to the LOI tests, the PLA with the OPS loading exhibited very small reduction of LOI. However, the CONE tests indicated that the OPS could improve the flame retardancy of the PLA by means of low peak heat release rate and average heat release rate. It was obtained that the degree and type of the PLA crystalline for the pure PLA and PLA/OPS affect their flame retardancy. In the max thermal decomposition stage of PLA and PLA/OPS, their gaseous products were similar; at high temperatures, the PLA/OPS produced simple and clear gaseous products of PLA with solid SiO 2 in the gas phase.
KW - crystallization
KW - flame retardancy
KW - polyhedral oligomeric silsesquioxane
KW - polylactic acid
UR - http://www.scopus.com/inward/record.url?scp=85058565079&partnerID=8YFLogxK
U2 - 10.1002/pat.4501
DO - 10.1002/pat.4501
M3 - Article
AN - SCOPUS:85058565079
SN - 1042-7147
VL - 30
SP - 648
EP - 665
JO - Polymers for Advanced Technologies
JF - Polymers for Advanced Technologies
IS - 3
ER -