Poly(L-lactide)/polypropylene blends: Evaluation of mechanical, thermal, and morphological characteristics (original) (raw)
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In this study, polylactic acid (PLA) was melt blended with polypropylene (PP) and liquid natural rubber (LNR) with the ratio of PLA/PP (90/10) and PLA/PP/LNR (90/10/10) in the Haake Rheomix internal mixer. The mechanical properties of such as stress- strain, flexural and impact were studied. It was found that the elongation at break, flexural and notched impact strength increased significantly for the LNR compatibilized PLA/PP blend. The DSC and FTIR showed the PLA/PP and PLA/PP/LNR were not miscible.
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Polylactide (PLA) polymer, polypropylene (PP) polymer, and a PLA/PP (70:30 wt%) blend, with liquid natural rubber−graft−methy methacrylate (LNR−g−MMA) of 0.0, 2.5, 5.0, and 10.0 phr as compatibilizers, were prepared by internal mixing and compression molding. The effect of LNR-g-MMA content on the morphology, mechanical properties, water absorption, thermal degradation, and a lifetime of blends based on PLA and PP was investigated. Scanning electron microscopy (SEM) revealed that the PLA/PP blend underwent phase separation, and the presence of LNR−g−MMA in the PLA/PP blend showed a more homogenized and refined blend morphology. Hence, the addition of LNR−g−MMA was used as a compatibilizer to induce miscibility in the PLA/PP blend. The values of tensile strength, elongation at break, and impact strength of the polymer blends increased, whereas water absorption values decreased with increased LNR−g−MMA content. Thermal degradation kinetics was studied over a temperature range of 50–80...
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The poly(lactic acid) (PLA) was melt blended with linear polyethylene glycol (PEG) in an effort to increase the toughness of PLA. Melt blending was carried out in an internal mixer at 180 o C mixing temperature with 50 rpm for 15 minutes. The blends were characterized in terms of mechanical, thermal and morphological properties. It was found that tensile and flexural strength, stiffness and notched Izod impact strength decreased significantly when the PEG was added to the PLA matrix at 2.5-10% of PEG concentrations. Both glass transition and melting temperatures (Tg and Tm) lowered as the concentration of PEG was increased. Moreover, it was noted that the PLA/PEG blends showed a lower onset and peak degradation temperatures but with lower final degradation temperature as compared to the neat PLA. The morphological analysis revealed that the PEG was dispersed as droplets in the PLA matrix with a clear boundary between PLA matrix and PEG phases.
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Effects of Compatibilizer on Thermal and Mechanical Properties of PLA/NR Blends
Materials Science Forum, 2015
The aim of the research is to study the effects of compatibilizer on thermal and mechanical properties ofbiopolymer poly (lactic acid) (PLA) and natural rubber (NR) blends. PLA was blended with NR in the composition of 95/5 weight percentage with present of compatibilizer. The compatibilizers, PLA grafted maleic anhydride (MA) (PLA-g-MA) and NR grafted MA (NR-g-MA) were synthesized in a composition of 9 phr of MA by using internal mixer in presence of benzoyl peroxide (BPO). The formulations of PLA/NR blended with the compatibilizer were in the range of 1, 3, 5 and 10 wt.% of PLA-g-MA and NR-g-MA, respectively. Blending process was conducted using twin screw extruder then were pelletized and hot pressed before characterized. The mechanical (tensile, flexural, impact) and thermal properties of the blends was investigated and from the results, the addition of PLA-g-MA in PLA/NR blendimproved the impact strength and elongation at break of the blends as compared with neat PLA and PLA/NR blend without compatibilizer and for thermal stability, it only had a slight influence on the blends. Addition of NR-g-MA on contrary did not give improvement on mechanical properties but increasing in thermal stability.
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In this work poly(lactic) acid (PLA)/poly(butylene succinate-co-adipate) (PBSA) biobased binary blends were investigated. PLA/PBSA mixtures with different compositions of PBSA (from 15 up to 40 wt.%) were produced by twin screw-extrusion. A first screening study was performed on these blends that were characterized from the melt fluidity, morphological and thermo-mechanical point of view. Starting from the obtained results, the effect of an epoxy oligomer (EO) (added at 2 wt.%) was further investigated. In this case a novel approach was introduced studying the micromechanical deformation processes by dilatometric uniaxial tensile tests, carried out with a videoextensometer. The characterization was then completed adopting the elasto-plastic fracture approach, by the measurement of the capability of the selected blends to absorb energy at a slow rate. The obtained results showed that EO acts as a good compatibilizer, improving the compatibility of the rubber phase into the PLA matrix...
Journal of Applied Polymer Science, 2019
The melt compatibility between poly(L-lactide) (PLA) and polyamides (PAs) with related thermomechanical properties is addressed. A particular attention is paid to four commercial PAs with extrusion processing temperatures close to PLA (PA10-10 to PA12). PLA/PA blend morphologies without a compatibilizer are first revealed by scanning electron microscopy. PA12 displays the best droplet dispersion into PLA (D n 700 nm), whereas a poor interfacial adhesion is attested for PLA/PA10-10 blends. Interfacial tensions corroborate the PLA/PA10-10 incompatibility (γ 12 9 mN/m, 240 C) with decreasing γ 12 in the order PLA/PA10-10 > PLA/PA11 > PLA/PA12 (γ 12 2 mN/m). Surface tensions confirm the highest compatibility between PLA and PA12. Ductilities, toughnesses, and thermal resistances of PLA/PA blends are evaluated up to 40-wt % PA. Brittle-to-ductile transitions are observed for PA content higher than 30-wt % with the highest ductility for PLA/PA12, in accordance with their enhanced compatibility. Impact strengths display similar trends with a twofold increase for PLA/PA12. An outstanding synergy between PLA and PA is highlighted by dynamic mechanical analyses with heat deflection up to 130 C for PLA/PA blends. The synergy arises from a peculiar crystallization of PLA in the presence of PA. PLA/PA morphologies/interfaces can be consequently tuned by an appropriate PA choice with interesting improvements of thermomechanical properties for high-performance/durable applications.
Journal of Elastomers and Plastics, 2010
Melt blending of polylactic acid (PLA) and linear low density polyethylene (LLDPE) was performed to investigate the effects of LLDPE loadings on the morphology, mechanical and thermal properties of PLA/LLDPE blends. LLDPE was blended with PLA from 5—15 wt% and prepared by counterrotating twin-screw extruder followed by injection molding into test samples. The mechanical properties of the blends were assessed through tensile, flexural and impact testings while thermal properties were analyzed using differential ...
European Polymer Journal, 2013
Polylactide (PLA), a biodegradable polymer, produced from annually renewable natural resources, has a glass transition temperature in the range of 50-60°C and is stiff and brittle at room temperature. In this communication we demonstrate that blending of PLA with atactic poly([R,S]-3-hydroxy butyrate) (a-PHB) leads to significant improvement of drawability and impact strength. The blends of PLA with a-PHB are biodegradable, similarly to plain PLA, and can be considered as a potential material for packaging, especially for food.
Poly(lactic acid)/low density polyethylene polymer blends: preparation and characterization
Asia-Pacific Journal of Chemical Engineering, 2012
Poly(lactic acid) (PLA) was melt blended with low density polyethylene (LDPE) with the aim of replacing commodity polymers in future applications. Because cost of PLA is quite high, it is not economically feasible to use it alone for day to day use as a packaging material without blending. In this work, PLA was blended with LDPE in different ratios by using a laboratory scale single screw extruder. The prepared blends were characterized in terms of rheological and mechanical properties. Rheological properties were studied using a capillary rheometer, and the Bagley's correction was performed. True shear rate (g r), true shear stress (t r), true viscosity (r) and non-Newtonian index (n) were determined. The relationship between true viscosity and temperature was also studied, and the flow activation energy at a constant shear stress (E t) was determined. The mechanical properties of the blends were investigated on dog bone-shaped samples obtained by injection molding, tensile tests were performed using Testometric M350-10KN, stress at break, strain at break and Young's modulus were determined. Rheological results show incompatibility between the two polymers where the true viscosity of the blend decreased with increasing PLA content below the line of mixing rule, also it was found that the blend exhibits shear-thinning behavior over the range of the studied shear rates. The mechanical results also showed incompatibility between PLA and LDPE in the blend, where stress at break and Young's modulus of the blend increased with increasing PLA content, whereas strain at break of the blends was similar to that of neat PLA.