Study On The Manufacture Of Poly (Butylene Succinate-Co-Butylene Terephthalate)(Pbst)Spunbonded Nonwoven And Its Proerties

With the stable development of the global economy and the changing of people’s consumption patterns, the awareness of environmental protection and health consciousness were waked up. The environmental problems are getting more and more attention. Therefore, biodegradable materials have attracted people’s attention. Poly (butylene succinate-co-butylene terephthalate)(PBST) is the random copolymer which was made of the poly (butylene succinate)(PBS) and poly (butylene terephthalate)(PBT). It’s a kind of aliphatic/aromatic copolymer which combined good biodegradable of aliphatic polyesters with excellent thermodynamic properties and processing performance of aromatic polymer. PBST has become a hot spot of research at home and abroad. At present, the scholars have done a lot of research on thermodynamic performance, spinning technology, fiber’s structure and degradation property of PBST. But there has few works and achievement in the study on using spunbonded materials to making PBST nonwoven.Based on this background, this article conducted research on the basic properties of PBST and determined the process of the PBST spunbonded nonwoven. Through the exploration of each process parameter, the PBST spunbonded nonwoven has been processed successfully. The better process parameters were obtained as well, the temperature of screw area I was190℃, screw area II:195℃, screw area III:200℃, spinning temperature:205℃, metering pump speed:30r/min, tensile strength of airflow:60Hz, laying web speed:20m/min, temperature of smooth roller:135℃, temperature of embossing roller:140℃.The PBST spunbonded filament’s fineness, thermal properties, tensile properties were tested too. The test results show that the diameter of PBST spunbonded filament is21.27m, the linear density is4.26dtex, the melting point is172.60℃and the degree of crystallinity is29.51%. It also shows that thee tensile properties of PBST spunbonded filament is poorer than PET spunbonded filaments and PET fiber. This is mainly because the crystallinity of PBST was29.51%as it had not been fully drafted relatively, the macromolecular chains are not very neat. But the crystallinity of PET fiber can reach45%-60%, which is generally due to the mechanical draft and sufficient stretching. The characterized indicator parameters, pore size and microstructure of PBST spunbonded nonwoven were tested as well. The weight and thickness of PBST spunbonded nonwoven were400g/m2and1.31mm. The weight is a litter too large, so the process can be further optimized. And the average pore diameter is37.74μm, which means the distribution of pore size is uniform. What’s more, the SEM photograph indicated that the web is preferably formed with a smoothed surface, and the thickness of PBST spunbonded filaments shows high uniformity.The biodegradable properties were studied through the degradation experiments of PBST spunbonded nonwoven in different envirments (pH=4.5,9.5,7.0and lipase PS). Then measured the below evaluation index:weight loss rate, thermal performance changes, tensile properties changes and surface morphology changes. The results show that, the weight loss rate of PBST spunbonded nonwoven increased with the increasing of degradation time. Its melting points and enthalpy also increased significantly. This is because amorphous region degrade earlier than crystalline region, and the macromolecular chains were cut randomly so that mesophase of segment enhanced, and growth in the existing crystal, and thus the wafer thickness increased, the melting point increased. Tensile properties of PBST spunbonded filament reduced, and through the PBST spunbonded nonwoven morphology observation. The degradation can be seen in PBST spunbonded filament’s surface, which became irregularity, broken and even the holes and so on. The degradation level in different conditions followed by lipase PS> alkaline> acidic> neutral.