聚乙烯结晶度对银抗菌剂溶出的影响EI

采用双螺杆挤出的方法制备了低密度聚乙烯(LDPE)/玻璃载体银系抗菌剂(IONPURE)的抗菌塑料。用溶出伏安法测定了抗菌塑料中银离子的溶出速率,用差示扫描量热法(DSC)研究了抗菌LDPE的熔融和结晶行为,用XRD和POM对LDPE的晶形和结晶度进行了表征,结果表明,抗菌剂在LDPE中起到异相成核的作用,随着其含量从0%增加到8%,LDPE结晶度呈现先增加后下降的趋势,而晶粒尺寸则逐渐减小。同时,通过加速溶出实验研究了不同结晶度抗菌LDPE样品中银离子的溶出行为,发现样品结晶度越大,银离子溶出速率越小,并且随着在水中浸泡时间的延长,结晶度影响越发明显。

Influences of Different Mol Feed Ratio of Lactic Acid and Glycolic Acid on the Structure and Properties of Copolymer

Using L-lactic acid(L-LA) and glycolic acid(GA) as staring material,via direct melt copolycondensation,serial poly(lactic acid-glycolic acid)(PLGA) with different mol feed ratio were synthesized after 10h’s polymerization under 170 ℃ and 70 Pa,and 0.5% SnCl2 as catalyst.These polymers were characterized by FT-IR,DSC,X-ray diffraction etc.It is found that the change of mol feed ratio exercises a certain influence on dissolvability,η and crystallizability,but an inconspicuous influence on Tg.Except for PLLA,PLGA10/90 and PGA have crystalline structures,PLGA with other mole feed ratio has random structures.When the mol feed ratio of LA and GA is 20/80,both the intrinsic viscosity(η]) and η are higher than that of the other ratios.While the PLGA of mol feed ratio around 50/50 has lower intrinsic viscosity(η]) and η.Melt spinning of PLGA30/70 shows its spinnability.