中国塑料 ›› 2022, Vol. 36 ›› Issue (2): 33-40.DOI: 10.19491/j.issn.1001-9278.2022.02.006

• 材料与性能 • 上一篇    下一篇

聚(乳酸⁃乙醇酸)薄膜制备及其性能研究

孙滔, 杨青, 胡健, 王洋样, 刘博, 云雪艳, 董同力嘎()   

  1. 内蒙古农业大学食品科学与工程学院,呼和浩特 010018
  • 收稿日期:2021-09-16 出版日期:2022-02-26 发布日期:2022-02-23
  • 通讯作者: 董同力嘎(1972—),男,教授,从事食品保鲜与安全控制技术研究,dongtlg@163.com
    E-mail:dongtlg@163.com
  • 基金资助:
    国家自然科学基金资助项目(21965026)

Preparation and properties of poly(lactic acid⁃co⁃glycolic acid) film

SUN Tao, YANG Qing, HU Jian, WANG Yangyang, LIU Bo, YUN Xueyan, DONG Tungalag()   

  1. College of Food Science and Engineering,Inner Mongolia Agricultural University,Hohhot 010018,China
  • Received:2021-09-16 Online:2022-02-26 Published:2022-02-23
  • Contact: DONG Tungalag E-mail:dongtlg@163.com

摘要:

以左旋乳酸(L?LA)和乙醇酸(GA)为原料,利用一步法熔融共聚合成聚(乳酸?乙醇酸)(PLLGA)共聚物,通过差示扫描量热仪(DSC)对共聚物薄膜的结晶性能进行了表征,并利用Avrami方程对其进行了等温结晶动力学研究,通过万能拉伸试验机和压差法气体透过仪对共聚物薄膜的力学性能和气体阻隔性能进行测试。结果表明,PLLGA共聚物薄膜中GA的引入对材料结晶性能有较大影响,在GA含量为4 %(摩尔分数,下同)的PLLGA中,GA表现为成核剂作用,共聚物结晶比纯聚左旋乳酸(PLLA)薄膜快,半结晶时间减少;而在GA含量为8 %的PLLGA中,GA则表现出限制分子链运动的作用,破坏共聚物分子间的规整度,导致材料结晶性能大幅度降低,处于非晶态;随着GA含量的增加,PLLGA薄膜的拉伸强度和弹性模量逐步下降,而断裂伸长率大幅度增加,GA含量为8 %的PLLGA的断裂伸长率达到了130.1 %,是纯PLLA薄膜的21.3倍;同时,PLLGA薄膜的气体阻隔性显著增加,5 ℃时,相比于纯PLLA薄膜,GA含量为8 %的PLLGA薄膜的O2、CO2、N2透过量分别降低了47 %、41 %和39 %。

关键词: 聚乳酸, 聚(乳酸?乙醇酸), 结晶性能, 力学性能, 气体阻隔性

Abstract:

Poly(lactic acid?co?glycolic acid) (PLLGA) was synthesized through one?step melt copolymerization using lactic acid (L?LA) and glycolic acid (GA) as raw materials, and its mechanical properties, crystallization properties and gas barrier properties were investigated. The crystalline characteristics of the PLLGA film were analyzed through Avrami equation using differential scanning calorimetry, and its mechanical and gas penetration performance were evaluated using a universal tensile testing machine and a differential pressure permeability meter through a differential pressure method. The results indicated that the introduction of GA generated a greater influence on the crystalline properties of the PLLGA film. GA could act as a nucleation agent to generate a nucleating effect on the PLLGA with a GA mole fraction of 4 %. The PLLGA film exhibited a faster crystallization rate than pure PLLA film, and its semi?crystallization time decreased. When the PLLGA had a GA mole fraction of 8 %, GA restricted the movement of the molecular chain, destroying the regularity between the copolymer molecules. This leads to a significant reduction in the crystalline properties of the PLLGA, making it in the amorphous state. With an increase in the mass ratio of GA, the PLLGA film presented a gradual decrease in tensile strength and elastic modulus, while its elongation at break increased significant. The elongation at break of the PLLGA with a GA mole fraction of 8 % reached 130.1 %, which was 21.3 times the value of pure PLLA film. In addition, the gas permeability of the PLLGA film decreased. Compared with the pure PLLA film, the O2, CO2, and N2 permeability of PLLGA film with a GA mole fraction of 8 % at 5 ℃ were reduced by 47 %, 41 %, and 39 %, respectively.

Key words: poly(lactic acid), poly(lactic acid?glycolic acid), crystallization performance, mechanical property, gas barrier property

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