Enhanced Flexibility of Biodegradable Polylactic Acid/Starch Blends Using Epoxidized Palm Oil as Plasticizer (original) (raw)
Related papers
2015
Polylactic acid (PLA) is the most commercially available bio-based and biodegradable plastic at present. PLA has been used in plastic related industries including single-used containers, disposable and environmentally friendly packaging owing to its renewability, compostability, biodegradability, and safety. Although PLA demonstrates reasonably good optical, physical, mechanical and barrier properties comparable to the existing petroleum-based plastics, its brittleness and mold shrinkage as well as its price are the points to be concerned for the production of rigid and semi-rigid packaging. Blending PLA with other bio-based polymers including thermoplastic starch (TPS) is an alternative not only to achieve a complete bio-based plastic, but also to reduce the brittleness, shrinkage during molding and production cost of the PLA-based products. TPS is a material produced mainly from starch which is cheap, renewable, biodegradable, compostable, and nontoxic. It is commonly prepared by ...
International Journal of Molecular Sciences, 2012
In this work, poly(lactic acid) (PLA) a fully biodegradable thermoplastic polymer matrix was melt blended with three different epoxidized palm oil (EPO). The aim of this research was to enhance the flexibility, mechanical and thermal properties of PLA. The blends were prepared at various EPO contents of 1, 2, 3, 4 and 5 wt% and characterized. The SEM analysis evidenced successful modification on the neat PLA brittle morphology. Tensile tests indicate that the addition of 1 wt% EPO is sufficient to improve the strength and flexibility compared to neat PLA. Additionally, the flexural and impact properties were also enhanced. Further, DSC analysis showed that the addition of EPO results in a decrease in T g , which implies an increase in the PLA chain mobility. In the presence of 1 wt% EPO, TGA results revealed significant increase in the thermal stability by 27%. Among the three EPOs used, EPO(3) showed the best mechanical and thermal properties compared to the other EPO's, with an optimum loading of 1 wt%. Conclusively, EPO showed a promising outcome to overcome the brittleness and improve the overall properties of neat PLA, thus can be considered as a potential plasticizer.
Journal of Polymers and the Environment, 2018
The blends of polylactic acid plasticized with acetyl tributyl citrate (P-PLA) and thermoplastic wheat starch (TPS) were prepared by a co-rotating twin screw extruder and the effect of maleic anhydride grafted PLA (PLA-g-MA) content as reactive compatibilizer on blends compatibility through morphological, rheological and tensile properties of the blends was investigated. Considerable improvement in properties of P-PLA/TPS (70/30 w/w) blend with incorporating the optimum PLA-g-MA content of 4 phr was achieved as this blend exhibited better morphological and rheological properties with an increase by 158 and 276% in tensile strength and elongation at break, respectively, compared to the uncompatibilized blend. Also the thermal stability and moisture sorption properties of the blends as effected by TPS content were studied. Decreasing in thermal stability and increasing in equilibrium moisture content of the blends were observed with progressively increasing of TPS content. For prediction the moisture sorption behaviour of blends with various TPS contents at different relative humidity, the moisture sorption isotherm data were modeled by GAB (Guggenheim-Anderson-de Boer) model.
Malaysian Journal of Analytical Science, 2016
Petrochemical based polymers used in packaging materials are causing various environmental problems. Therefore, biopolymers prepared from renewable sources have high potential to substitute the commercially available non-degradable polymer. Poly(lactic acid) (PLA) is one of the biodegradable polymers that can be used to substitute in the application of petrochemicalbased polymers. Environmental friendly and biodegradable epoxidized palm oil (EPO) was used as plasticizer in this study and it was incorporated into PLA matrix through solution blending method. The mechanical properties were determined through three-point flexural test and tensile test. Tensile results revealed that the flexibility of PLA can be improved by the addition of epoxidized palm oil (EPO) as plasticizer in the polymer. PLA/EPO blend at ratio 100:10 showed significant flexibility among the other PLA/EPO blends. The thermal properties of neat PLA and PLA/EPO blends were characterized by using Differential Scanning Calorimetry (DSC). The glass transition temperature (Tg) decreased by addition of plasticizer, indicated the chain mobility of PLA increased in the PLA/EPO blends system. The improved flexibility of PLA by using EPO as plasticizer showed that it has high potential to be used as environmental-friendly packaging material.
Macromolecules, 2016
Polylactide (PLA), a commercially available thermoplastic derived from plant sugars, finds applications in consumer products, disposable packaging, and textiles, among others. The widespread application of this material is limited by its brittleness, as evidenced by low tensile elongation at break, impact strength, and fracture toughness. Herein, a multifunctional vegetable oil, acrylated epoxidized soybean oil (AESO), was investigated as a biodegradable, renewable additive to improve the toughness of PLA. AESO was found to be a highly reactive oil, providing a dispersed phase with tunable properties in which the acrylate groups underwent cross-linking at the elevated temperatures required for processing the blends. Additionally, the presence of hydroxyl groups on AESO provided two routes for compatibilization of PLA/AESO blends: (1) reactive compatibilization through the transesterification of AESO and PLA and (2) synthesis of a PLA star polymer with an AESO core. The morphological, thermal, and mechanical behaviors of PLA/oil blends were investigated, in which the dispersed oil phase consisted of AESO, soybean oil (SYBO), or a 50/50 mixture of AESO/SYBO. The oil additives were found to toughen the PLA matrix, with significant enhancements in the elongation at break and tensile toughness values, while maintaining the glass transition temperature of neat PLA. In particular, the blend containing PLA, AESO, SYBO, and the PLA star polymer was found to exhibit a uniform oil droplet size distribution with small average droplet size and interparticle distance, resulting in the greatest enhancements of PLA tensile properties with no observable plasticization.
Compatibilized Polylactic Acid/Therm oplastic Starch by Reactive Blend
The aim of this work was to study reactive blending of polylactic acid (PLA) and thermoplastic starch (TPS). Two types of TPS, one with reactive agents and one without, were prepared by mixing 30wt% of starch with glycerol in twin screw extruder. The as-prepared TPS was blended with PLA together with reactive agents in twin screw extruder. The blend ratios of PLA:TPS were 70:30 and 50:50. The samples were characterized by tensile testing, scanning electron microscope (SEM) and differential scanning calorimeter (DSC). For all blends ratios, the tensile strengths of PLA/TPS reactive blends were higher than the physical blend of PLA/TPS. When compared the same ratios of the blend (50:50), the system consisting of PLA, TPS prepared without reactive agents, maleic anhydride and peroxide exhibited the highest %strain. The differential thermal analysis indicated that the crystallization temperature of the reactive blend of PLA/TPS shifted to a lower temperature compared to the physical blend of PLA/TPS. This suggested that the compatibility between TPS and PLA was improved for the reactive blend system. Most of PLA/TPS reactive blends showed the better water resistance compared to the physical blend of PLA/TPS.
Polymers for Advanced Technologies, 2018
Polylactic acid (PLA) and thermoplastic starch (TPS) are known as bio-based and biodegradable thermoplastic polymers that can be used in different applications owing to their inherent physical and mechanical properties. In order to reduce the higher costs of PLA and tuning its physical and mechanical properties suitable for short life packaging applications, blending of PLA with the TPS, more economical biodegradable polymer, has been considered in academic and industrial researches. However, melt blending of PLA with TPS without compatibilization process caused some drawbacks such as coarsening morphology and declining mechanical properties and ductility because of thermodynamic immiscibility, which may restrict its usage in packaging applications. Subsequently, our approach in this research is compatibilization of PLA/TPS blends by utilization of primary well tuning of TPS formulation with a combination of sorbitol and glycerol plasticizers. In this work, the wide composition range of melt mixed PLA/TPS blends was prepared using a laboratory twin screw extruder. The effects of microstructure on the rheological and mechanical properties of PLA/TPS blends were studied using different methods such as scanning electron microscopy (SEM) images, contact angle, oscillatory shear rheological measurements, and tensile and impact strength mechanical tests. The rheological and mechanical properties were interpreted according to the morphological features and considering the possibility of plasticizer migration from TPS to PLA phase during melt blending. Reduction in complex viscosity and storage modulus of PLA matrix samples indicates the improved melt processability of blends. Finally, in comparison with mechanical results reported in literature, our simple approach yielded the blends with elastic modulus and ductility comparable with those of chemically compatibilized PLA/TPS blends.
IJMS , 2024
This study provides an in-depth analysis of mechanical, thermal, and biodegradability characteristics of bioplastics: pure polylactic acid (PLA), starch-based bioplastics, and PLA-starch composites. Through tensile testing, elastic modulus evaluation, and thermal gravimetric analysis (TGA), alongside soil burial tests for biodegradability, this research aims to assess the performance and environmental impact of these materials. PLA demonstrated superior mechanical strength and thermal stability, whereas starch-based bioplastics exhibited higher biodegradability. PLA-starch composites offer a balanced approach, merging improved biodegradability with enhanced mechanical properties. This detailed evaluation aids in the informed selection of bioplastic materials for diverse applications.
Polymers
In previous research, a polylactic chitin starch composite was prepared without the use of a solvent to enhance the miscibility. In this study, a polylactic acid (PLA) chitin starch composite was produced with chloroform as a plasticizer in the ratio 1:10. The blending of chitin and starch with PLA ranges from 2% to 8%. Tensile strength, impact, thermogravimetry analysis-Fourier-transform infrared spectroscopy (TGA)-FTIR, and differential scanning calorimetry (DSC) were used to test the thermomechanical properties. Also, the morphological properties, water absorption, and wear rate of the material was observed. The results showed that the tensile strength, yield strength, and impact strength were improved compared to the pure polylactic acid. Also, the elastic modulus of the samples increased, but were lower compared to that of the pure polylactic acid. The result of the fractured surface morphology showed good miscibility of the blending, which accounted for the good mechanical pro...