Production and investigation of structure and properties of polyethylene–polylactide composites

Abstract

Under conditions of shear deformations, low‐density polyethylene (LDPE) and polylactide (PLA) composites are obtained in rotor disperser. The production of these composites allows one to use polymers derived from natural raw and to reduce the cost of the materials on their base. The addition of rigid PLA leads to increase in elastic modulus from 200 for LDPE to 1190 for LDPE–PLA (50:50 wt %) composites and in tensile strength from 13.3 for LDPE to 17.8 for LDPE–PLA. By differential scanning calorimetry method, it is shown that LDPE and PLA are incompatible. Using X‐ray diffraction analysis, it is found that degree of crystallinity of composites decreases from 46.1 at 50:50 wt % to 36.9 at 80:20 wt % component ratios with the rise in LDPE content. Tests on fungus resistance show that the composites containing 50 wt % PLA are more resistant than the composites containing 30 wt % PLA. First by gel‐permeation chromatography method, it is shown that composite degradation after exposure in soil is accompanied by the PLA chain scission and depolymerization with formation of monomers and dimers (M w of PLA decreases from 118,860 to 80,100). The obtained composites can be applied as packaging materials. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47598.

Novel biodegradable low‐density polyethylene–poly(lactic acid)–starch ternary blends

“…The mechanical parameters of the LDPE–PLA–starch ternary blends under investigation and similar characteristics of the LDPE–starch, [ 12 ] LDPE–PLA, [ 15 ] and PLA–starch [ 25 ] binary blends previously obtained are presented in Table 1. As can be seen, the addition of such rigid polymers as PLA and starch to LDPE leads to an increase in the elastic modulus E , 1190 MPa in the case of LDPE–starch (50:50 wt%).…”

“…Authors showed in ref. [12,25,15] when studying the LDPE-starch, PLA-starch, and LDPE-PLA blends that mechanical properties and biodegradability depend on the component ratio both for the LDPE blends with natural polymers and blends based on two polymers of natural origin. Based on present knowledge, the LDPE blends with polysaccharide starch with addition of a second polymer of natural origin PLA were obtained and studied in this work.…”

“…The authors have previously obtained the PLA–starch, [ 25 ] LDPE–starch, [ 12 ] , and LDPE–PLA [ 15 ] blends under the action of shear deformations at solid‐phase mixing and explored their structure, mechanical, thermophysical properties, and also biodegradability. For the first time, it has been shown that there is almost no PLA biodegradation at the exposure of samples in the soil using the gel‐penetrating chromatography (GPC) method.…”

“…There are a number of works devoted to the production of LDPE blends with thermoplastic polyester poly(lactic acid) (PLA), synthesized from natural raw materials (lactic acid), which is an alternative to polymers derived from oil. [15][16][17][18][19][20] However, despite its origin, PLA degrades easily only under severe conditions (compost or seawater). Since the properties of PLA are similar to the properties of a number of synthetic polymers, it is often used to obtain the polymer blends.…”

The effect of electrospun polylactic acid/chitosan nanofibers on the low density polyethylene/ploy lactic acid film as bilayer antibacterial active packaging films

“…Over the past 20 years, PLA has received increasing attention due to its biodegradability, low gas emission, and low toxicity in food packaging applications (Arslan & Dilsiz, 2020; Trongsatitkul & Chaiwong, 2017). The most important feature of PLA, which is of industrial importance, is that it can be processed by conventional plastic processing instruments (DeGruson, 2016; Rogovina et al., 2019). PLA is used in electrospinning process of Ch to make an antibacterial coating of PLA/Ch nanofiber on the surface of low‐density polyethylene (LDPE)/PLA composite films.…”