退火处理对挤出发泡聚乳酸结晶度的影响.pdf

第43卷第11期
塑料工业
2015年11月
CHINA PLASTICS INDUSTRY
成型加到退火处理对挤出发泡聚乳酸结晶度的影响”
与设备
朱文利2,朱定见'“
(1.湖北文理学院机械与汽车工程学院,湖北襄阳441053;
2.汽车零部件制造装备数字化湖北省协同创新中心,溯北襄阳41053)
摘要:以超临界CO2为发泡剂(质量分数9%),利用单螺杄挤出机在不同口模温度下制备了线型和支链型聚乳
酸(PLA)发泡样品。研究发现,支链型PIA因具有较高的熔体强度,所以其挤出发泡的加工窗口比线型PLA宽
且支链型PLA发泡样品的泡孔密度较高、泡孔尺寸较小、体积膨胀倍数较大、泡孔开孔率较低。PLA因结晶缓慢孚
致挤出发泡样品的结晶度不足10%,但退火处理可在较短的时间内(10min)将线型PLA发泡样品的结晶度提高到
18%左右,而支链型PLA发泡样品的结晶度可提高至40%。
关键词:聚乳酸;支链;结晶度;退火
DOI:10.3969/j-isn.1005-5770.2015.1.010
中图分类号:TQ323.4
文献标识码:A
文章编号:1005-5770(2015)11-0039-04
Effect of Annealing on the Crystallinity of Extruded Polylactide Foams
ZHU Wen-li, ZHU Ding-jian
(]. School of Mechanical and Automobile Engineering, Hubei University of Arts and Science, Xiangyang441053, China;
2. The Collaboratie Innovation ener of Hei Prone for Au Pas Manu urin upm Digitization, Xiangyang441053, China)
Abstract: Both linear and chain-branched polylactide(PLA) foams were prepared under different die
temperatures via a single-screw extruder with supercritical CO (9wt%)as a blowing agent. The research
results show that because chain-branched PLA has the relatively high melt strength, it has advantages in the
extrusion processing window wider than that for foaming linear PLA. Moreover, for chain-branched PLA
foamed samples, the cell density is relatively high, the cell size is relatively small, and the volume
expansion ratio and the open cell content are relatively low. The crystallinity of all the foamed samples is less
than 10% due to inherently slow crystallization of PLA. However, by the annealing treatment for a very short
time (10 min), the crystallinity of foamed samples increases to 18% for linear PLA and up to 40% for
chain-branched PLA
Keywords: Polylactide; Branched-chain; Crystallinity; Annealing
聚乳酸(PIA)来源于农作物,具有良好的生物品的结晶度,从而改善其力学性能和物理性能°。
相容性和生物可降解性,是一种绿色环保的塑料原本研究分别采用线型和支链PLA,以超临界CO2为发
料2。随着合成技术的不断进步、生产成本的逐步泡剂,在单螺杆挤出机不同口模温度下制备了发泡样
降低,PLA制品大有替代传统塑料制品的趋势。线型品,对比了线型和支链PILA的发泡性能并研究了退
结构的PLA早在半个世纪前就已被开发出来,但由火处理对发泡样品结晶度的影响。
于熔体强度低,不适于挤出发泡生产。通过扩链剂改
性的支链PLA熔体强度高,制备的泡沫产品可与传1实验部分
统塑料制品相媲美341。然而,PLA结晶缓慢,其玻
1.1实验原料
璃化转变温度(7)只有65℃左右,直接挤出发泡
PLA: Ingeo2003D(线型)和8052D(支链
的产品耐热性差,严重影响了制品的应用范国。将泡型),密度为1.25g/cm,美国 Natureworks公司;发
沫制品加热到T以上对其进行退火处理可以提高制泡剂:食品级CO2,纯度99.5%,裹阳市博一化工
*国家自然科学基金资助项目(51403059),湖北省自然科学基金资助项目(2014CFB456),襄阳市科技计划研究与开发项
目(襄科业[2013]66号)*本通信作者
作者简介:朱定见,男,1970年生,副教授,研究方向是精密仪器和测量、机械制造及自动化。hustzdje0163.com