Abstract
Polylactic acid (PLA) is limited in its application due to its high price, high brittleness and low glass-transition temperature. Modification methods are currently used to overcome these shortcomings. In this study, Bletilla striata polysaccharide (BSP) was blended with PLA by a solvent method. DMA data showed that the BSP/PLA film had a higher glass-transition temperature, and the glass-transition temperature of the film showed an extreme value of 68 °C when the proportion of the chalk polysaccharide was 0.8%. TG data indicates that the composite film material has good thermal stability. Tensile tests show that the composite film is improved in rigidity and elasticity compared to the pure PLA film. The blending modification of PLA with white peony polysaccharide not only reduces the cost of PLA, but also improves the thermal and mechanical properties of PLA.
Highlights
Extracted from Radix Paeoniae Alba, Bletilla striata polysaccharide (BSP), known as Bletilla hyacinthina gumis, is a polymer with low toxicity and high safety
The differential scanning calorimetry (DSC) and dynamic thermomechanical analysis (DMA) data can both reflect the Tg of the BSP/Polylactic acid (PLA) composite films
The DSC curves of pure PLA and PLA modified with different ratios of BSP are shown in Figure 3, and the obtained parameters are shown in Table 2 (Tc is the cold crystallization temperature of the material, ∆Hc is the enthalpy of crystallization, Tm is the melting temperature, ∆Hf is the enthalpy of fusion, and Xc is the crystallinity)
Summary
Extracted from Radix Paeoniae Alba, Bletilla striata polysaccharide (BSP), known as Bletilla hyacinthina gumis, is a polymer with low toxicity and high safety. PLA has a wide range of applications and is easy to process It is a green polymer with excellent performance and can blend with other natural polymer materials to form. Wu et al [32] observed increased tensile strength and elongation at break for a polylactic acid grafted starch/PLA composite but it had a significantly decreased initial thermal decomposition temperature and deteriorated thermal stability. The obtained PLA composites have increased tensile strength and elongation at break, excellent toughness but poor thermal stability. The obtained materials have the advantages of high elongation at break, high impact strength and high tensile strength but exhibit no improvement in thermal properties. The results show that the obtained composite exhibits improved thermal properties and improved mechanical properties, which is a new highlight in PLA blend modification research. The mechanical properties of the composite film were tested on a tensile testing machine
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