材料期刊网

聚丁二酸丁二醇酯(PBS)综合性能优越,但因熔体黏度低而难以用于制备微孔塑料.论文采用离子化改性提高PBS熔体黏度,用于超临界二氧化碳(sc-CO2)发泡.将丁二酸与丁二醇预缩聚后,添加二乙醇胺盐酸盐和二异腈酸六亚甲基酯(HDI)进行扩链反应,制备氨基离子浓度(UIC)为1％ ～5％的PBS离聚物(PBSUI),再以sc-CO2发泡制备PBSUI微孔塑料.采用动态流变仪和X射线衍射测试PBSUI的流变行为和结晶性能,随着UIC的增加,由离子簇聚集产生的物理交联提高了PBSUI的熔体黏度和松弛时间,发泡前后PBSUI结晶度和球晶的直径均降低.扫描电镜结果表明,随着UIC增加,PBSUI泡孔由圆形转变为多边形,泡孔平均直径(D)、壁厚和开孔率下降,而泡孔密度(Nf)和发泡倍率则上升.当UIC为3％,PBSUI的D为2.05 μm,Nf达1.73×1010 cm-3,发泡倍率超过10,由离子簇聚集引起的物理交联和异相成核作用,显著提高了PBSU的发泡性能,获得了泡孔形态良好的微孔泡沫塑料.

Poly(butylene succinate) (PBS) is regarded as one of the most promising biodegradable polymers due to the excellent mechanical properties,thermal stability,and thermo-process.However,due to its low melt viscosity,PBS microcellular foam is difficult to fabricate by using supercritical CO2 foaming.To improve its viscoelasticity and foamability,PBS was modified through ionizing in this paper.The segmented PBS urethane ionenes (PBSUI)containing secondary amine cation were synthesized by chain extension reaction of dihydroxyl terminated poly (butylene succinate) and diethanolamine hydrochloride (DEAH) in the presence of hexamethylene diisocyanate (HDI).Then the PBSUI foams were fabricated by supercritical CO2 in a rapid depressururization process via batch foaming method.Rotational rheometer and XRD were used to characterize the rheological and crystalline properties of PBSUI.The results reveal that the melt viscosity and relaxation time of PBSUI increase with rise of the urethane ionic group content,while both the crystallinity and spherulitic diameter of foaming PBSUI and unfoaming PBSUI decrease.The results of SEM demonstrate that the foam shape of PBSUI transforms from circle into polygon with increasing the urethane ionic group content.Moreover,both the cell density and expansion volume ratio increase,while the average cell diameter,the cell wall thickness and the cell opening ratio decrease when the urethane ionic group content increases from 1％ to 5 ％.PBSUI foam with 3 ％ urethane ionic group could achieve micro cell,the average cell diameter is 2.05μm,the cell density is 1.73 × 1010 cm-3 and the expansion volume ratio is more than 10.The results illuminate that when urethane ionic group is introduced into PBS,and PBSU microcellular foam is successfully prepared by supercritical carbon dioxide.The reason is attributed to physical crosslinking and heterogeneous nucleation effect caused by ion clusters aggregation,and the PBSU foaming performance is significantly improved.