Mechanical Properties of Poly(lactic acid) / Thermoplastic Starch Blends Crosslinked by Gamma Radiation

2013 ◽  
Vol 781-784 ◽  
pp. 467-470 ◽  
Author(s):  
Siriruck Kalapakdee ◽  
Thirawudh Pongprayoon ◽  
Kasinee Hemvichian ◽  
Phiriyatorn Suwanmala ◽  
Wararat Kangsumrith
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Gamma Radiation ◽  
Crosslinking Agent ◽  
Thermoplastic Starch ◽  
Poly Lactic Acid ◽  
Optimum Dose ◽  
Gel Fraction ◽  
Twin Screw ◽  
Starch Blends

This research aims to determine the influences of radiation-induced crosslinking on the mechanical properties of polymer blends between poly (lactic acid) (PLA) and thermoplastic starch (TPS). PLA and TPS were mixed at different ratios (90:10, 80:20, 70:30, 60:40) in the presence of a crosslinking agent using a twin screw extruder. The blends were compression molded into films. The film samples were irradiated by gamma radiation at different doses. Gel fraction was used to determine crosslinking efficiency. Results showed that gamma radiation was able to induce crosslinking for PLA/TPS blends. The gel fraction and mechanical properties decreased with increasing TPS content. The optimum ratio of PLA:TPS with the maximum gel fraction and mechanical properties was 90:10 and the optimum dose was 40 kGy by gamma radiation.

Poly(Ethylene Glycol) as a Compatibilizer for Poly(Lactic Acid)/Thermoplastic Starch Blends

2012 ◽  
Vol 21 (1) ◽  
pp. 151-159 ◽  
Author(s):  
Márcia Maria Favaro Ferrarezi ◽  
Márcia de Oliveira Taipina ◽  
Laura Caetano Escobar da Silva ◽  
Maria do Carmo Gonçalves
Keyword(s):  
Lactic Acid ◽  
Ethylene Glycol ◽  
Thermoplastic Starch ◽  
Poly Lactic Acid ◽  
Poly Ethylene Glycol ◽  
Starch Blends ◽  
Poly Ethylene

Preparation of modified starch-grafted poly(lactic acid) and a study on compatibilizing efficacy of the copolymers in poly(lactic acid)/thermoplastic starch blends

2012 ◽  
Vol 126 (S1) ◽  
pp. E389-E396 ◽  
Author(s):  
J. Wootthikanokkhan ◽  
P. Kasemwananimit ◽  
N. Sombatsompop ◽  
A. Kositchaiyong ◽  
S. Isarankura na Ayutthaya ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Thermoplastic Starch ◽  
Poly Lactic Acid ◽  
Modified Starch ◽  
Starch Blends

Effect of Compatibilizers on Composite Materials of Bio-Ethanol Byproduct-Poly(lacticacid)

2012 ◽  
Vol 204-208 ◽  
pp. 4088-4092
Author(s):  
Ming Ming Zhang ◽  
Xiao Huan Liu ◽  
Chun Peng Wang ◽  
Li Wei Jin
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Composite Materials ◽  
Extrusion Process ◽  
Poly Lactic Acid ◽  
Twin Screw Extrusion ◽  
Screw Extrusion ◽  
Twin Screw ◽  
Process Effects ◽  
Properties Of Composites

The blend composite materials of bio-ethanol byproduct-Poly(lactic acid) (PLA) were produced by a twin-screw extrusion process. Effects of bio-ethanol byproduct (BEB) contents and different compatibilizers on properties of composite materials were investigated. The research showed that with the increase of contents of bio-ethanol byproduct, the mechanical properties decreased. The mechanical properties of composites were improved by adding the compatibilizers, especially the polypropylene grafted maleic anhydride (PP-MAH). When the PP-MAH content was 2.5%, the mechanical properties of the composite materials were superior to others.

Effect of blending conditions on mechanical, thermal, and rheological properties of plasticized poly(lactic acid)/maleated thermoplastic starch blends

2011 ◽  
Vol 124 (2) ◽  
pp. 1012-1019 ◽  
Author(s):  
J. Wootthikanokkhan ◽  
N. Wongta ◽  
N. Sombatsompop ◽  
A. Kositchaiyong ◽  
J. Wong-On ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Rheological Properties ◽  
Thermoplastic Starch ◽  
Poly Lactic Acid ◽  
Starch Blends

scholarly journals Properties of Poly(Lactic Acid) Filled with Hydrophobic Cellulose/SiO2 Composites

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Kittithorn Lertphirun ◽  
Kawee Srikulkit
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Hydrolytic Degradation ◽  
Poly Lactic Acid ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Twin Screw ◽  
Hydrolysis Of Cellulose ◽  
One Step ◽  
Hydrolysis Of

Hydrophobic cellulose/SiO2 composites were prepared. Resultant hydrophobic cellulose/SiO2 composites were melt mixed with PLA using a twin-screw extruder to obtain 10 wt% masterbatch. Again, 10 wt% masterbatch was melt mixed with virgin PLA, resulting in PLA containing hydrophobic cellulose/SiO2 at various contents (1 wt%, 3 wt%, and 5 wt%) using a twin-screw extruder (barrel zone temperature: 150/160/170/180/190°C (die zone)). Injection-molded samples were prepared for mechanical properties evaluation. Results showed that poor mechanical properties found at low percent loadings were associated with a significant depolymerization of masterbatch composition due to twice thermal treatments. Note that 10 wt% masterbatch was subjected to injection molding straight away in a one-step process. Results showed that 10 wt% hydrophobic cellulose/SiO2/PLA composites exhibited mechanical properties equivalent to neat PLA. Importantly, the addition of hydrophobic cellulose/SiO2 at high percent loading could favor landfill degradation of PLA via water absorption ability of cellulose. It was expected that enzymatic hydrolysis of cellulose resulted in the formation of lactic acid and silicic acid which consequently catalyzed the hydrolytic degradation (acid hydrolysis) of PLA. The hydrolytic degradation produced carboxylic acid end group which further accelerated the degradation rate.

scholarly journals Study of the Physical and Mechanical Properties of Thermoplastic Starch/Poly(Lactic Acid) Blends Modified with Acid Agents

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 578
Author(s):  
Carolina Caicedo ◽  
Heidy Lorena Calambás Pulgarin
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Organic Acids ◽  
Physical And Mechanical Properties ◽  
Thermoplastic Starch ◽  
Poly Lactic Acid ◽  
Thermal Transitions ◽  
Surface Polarity ◽  
Acid Agent ◽  
Structural Affinity

In this work, we present a functionalization strategy of starch-poly(lactic acid) (PLA) blends with organic acids. Lactic and acetic acid were used as acid agents, and oleic acid was also included in the previous acids, with the aim of finding a synergy that thermodynamically benefits the products and provides hydrophobicity. The ratio of starch and sorbitol was 70:30, and the added acid agent replaced 6% of the plasticizer; meanwhile, the thermoplastic starch (TPS)–PLA blend proportion was 70:30 considering the modified TPS. The mixtures were obtained in a torque rheometer at 50 rpm for 10 min at 150 °C. The organic acids facilitated interactions between TPS and PLA. Although TPS and PLA are not miscible, PLA uniformly dispersed into the starch matrix. Furthermore, a reduction in the surface polarity was achieved, which enabled the wettability to reach values close to those of neat PLA (TPS–L-PLA increased by 55% compared to TPS–PLA). The rheological results showed a modulus similar to that of TPS. In general, there were transitions from elastic to viscous, in which the viscous phase predominated. The first and second-order thermal transitions did not show significant changes. The structural affinity of lactic acid with biopolymers (TPS–L-PLA) allowed a greater interaction and was corroborated with the mechanical properties, resulting in a greater resistance with respect to pure TPS and blended TPS–PLA (28.9%). These results are particularly relevant for the packaging industry.

scholarly journals Mechanical Properties of Starch and Poly(lactic acid) Biodegradable Sheets Added of Carboxylic Acids

2014 ◽  
Vol 5 (2) ◽  
pp. 26
Author(s):  
Marianne Ayumi Shirai ◽  
Juliano Zanela ◽  
Fabio Yamashita
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Citric Acid ◽  
Relative Humidity ◽  
Carboxylic Acids ◽  
Thermoplastic Starch ◽  
Poly Lactic Acid ◽  
Elongation At Break ◽  
Biodegradable Packaging ◽  
Hydrophobic Nature

<p><em>Thermoplastic starch and poly(lactic acid) (PLA) blends have been studied as potential materials for the production of biodegradable packaging. However due to the hydrophilic characteristic of starch and hydrophobic nature of PLA, these polymers are incompatible at microscopic level and this fact interfere significantly in the mechanical properties of the obtained materials. Several compatibilizer have been investigated to improve the compatibility between these polymers, including carboxylic acids. Thus, this study evaluated the mechanical properties of thermoplastic starch and PLA sheets added of citric and adipic acids produced by flat extrusion (calendaring-extrusion) and stored at different relative humidity. The sheets containing citric acid were thinner, more resistant and showed higher values of elongation at break. The relative humidity of storage interfered significantly in the mechanical properties, possibly due to the plasticizing effect of water. Citric acid was an additive which improved the mechanical properties of the starch and PLA sheets produced by flat extrusion. Furthermore, it is important to control the relative humidity of storage to not alter the mechanical properties of the starch based blends.</em></p><p>DOI: 10.14685/rebrapa.v5i2.164</p><p><em><br /></em></p>

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