聚合物挤出热压印成型工艺

介绍一种新的连续热压印工艺,此工艺中热压印机与聚合物片材挤出机串联使用,聚合物片材经挤出机挤出以后先要对其进行压平和调厚,以保证待压印片材的厚度及其均匀性,然后再进行热压印步骤。分析了热压印中影响压印制品质量的关键因素以指导热压印机的设计。应用此工艺结合所设计的压印机成功制备出了聚合物微透镜扩散板,并对制备出的扩散板的光学性能进行了模拟和测试。此工艺流程具有设备简单、图形复制精度高、效率高、成本低等优点,非常适合大面积微结构的制备。

Microstructure and mechanical properties of Al−Mg−Si alloy U-shaped profile

To get a full understanding of hot extrusion,solid solution treatment and aging process on the Al−0.56Mg−0.63Si alloy,the microstructure and mechanical properties of a U-shaped profile were studied through optical microscopy,scanning electrical microscopy,transmission electrical microscopy,hardness,and tensile tests.The coarse equiaxed grains existed near the profile edge as a result of the dynamic recrystallization nucleation and exceeding growth during hot extrusion.The fibrous deformed and sub-structured grains located between the two coarse grain layers,due to the occurrence of work-hardening and dynamic recovery.Perpendicular needle β′′precipitates were distributed inside the grain,and obvious precipitates-free zone appeared after aging treatment.The tensile strength,yield strength and elongation of the aged Al−Mg−Si alloy U-shaped profile were no less than 279.4 MPa,258.6 MPa,and 21.6%,respectively.The fracture morphology showed dimple rupture characteristics.The precipitates and grain boundaries played key role in the strengthening contribution.

高载药量尼莫地平固体分散体的制备及其性能表征

将尼莫地平与聚合物载体照质量比4∶1混合,采用热压挤出法制备了高载药量尼莫地平固体分散体。以制品在pH 1.0盐酸中的溶出行为为评价指标,优化了载体材料种类、挤出转速、挤出温度和制备方法。结果显示,在远低于尼莫地平熔点的80℃条件下,以30 r/min的转速通过热压挤出法制备的高载药量尼莫地平-Eudragit®EPO固体分散体,能显著提高尼莫地平的溶出度,15 min溶出率达80%以上。差示扫描量热、粉末X射线衍射、粒径测定和扫描电镜表征结果显示,固体分散体中药物以纳米晶形式存在。加速稳定性试验中,固体分散体中的尼莫地平由晶型Ⅰ转变为晶型Ⅱ,但体外溶出行为基本不变。