高柔性聚乳酸薄膜的制备及对口蘑的保鲜效果

目的 为了改善聚L-乳酸(PLLA)的柔韧性和气体选择透过性，将聚富马酸二元醇酯(PNF)作为柔性链段以熔融共聚方式引入PLLA中对其进行改性。方法 以PLLA为主体，加入PNF，并改变其中二元醇链段长度制备一系列聚乳酸-共富马酸二元醇酯(PLNF)共聚物，随后将其制备成薄膜，测试其力学性能、气体透过性能和水蒸气透过性，并对口蘑进行贮藏试验。结果 PNF的加入使PLLA的力学性能、气体选择透过性及透湿性均得到改善，且断裂伸长率是随着二元醇链段的增长而逐渐增大。与PLLA相比，聚乳酸-共富马酸癸二醇酯(PLDF)的断裂伸长率可达346.4%，聚乳酸-共富马酸丁二醇酯(PLBF)的CO2/O2选择透过比从3.0升高到4.4，且在口蘑贮藏期间可维持其形态，呈现较好的感官品质，在15 d内仍具食用价值。结论 PNF的引入有效改善了PLLA的性能，延长了口蘑的货架期，为PLLA薄膜进一步用于生鲜果蔬包装提供了参考。

Preparation of Highly Flexible Poly (Lactic Acid) Films on the Storage Quality of Portobello Tricholoma Mongolicum Imai.

The work aims to introduce poly ( N-diol fumarate) (PNF) into PLLA as a flexible chain segment by melt copolymerization to complete the modification, so as to improve the flexibility and gas selective permeability of PLLA. A series of poly (L-lactic acid-diol fumaric) (PLNF) copolymers were prepared with PLLA as the main component by adding PNF and changing the length of the diol chain segments therein, which were subsequently prepared into films, tested for mechanical properties, gas permeability, and water vapor permeability, and subject to storage tests on portobello Tricholoma mongolicum Imai. The mechanical properties, gas selective permeability, and moisture permeability of PLLA were improved by the addition of PNF. Compared with PLLA, the elongation at break of poly (L-lactic acid-decanediol fumaric) (PLDF) could reach 346.4%, the selective permeability ratio of CO2/O2 of poly (L-lactic acid-butyrate fumaric) (PLBF) increased from 3.0 to 4.4. During the whole storage process, the Tricholoma mongolicum Imai. could maintain morphology, present better sensory quality, and still have edible value within 15 d. The addition of PNF effectively improves the properties of PLLA and increases the shelf life of Tricholoma mongolicum Imai., which provides a reference for the further use of PLLA films for fresh fruit and vegetable packaging.