Toughness Enhancement of Polylactic Acid by Employing Glycolyzed Polylactic Acid-Cured Epoxidized Natural Rubber

2014 ◽  
Vol 1025-1026 ◽  
pp. 580-584 ◽  
Author(s):  
Phrutsadee Sukpuang ◽  
Mantana Opaprakasit ◽  
Atitsa Petchsuk ◽  
Pakorn Opaprakasit

Glycolyzed polylactic acid (GPLA)-cured epoxidized natural rubber (ENR) is developed for use as a toughening agent for PLA resin. GPLA is obtained from chemical recycling of PLA resin by a glycolysis reaction. GPLA-cured ENR is then prepared by the crosslinking reaction of ENR with GPLA in an internal mixer. Chemical structures of the cured products are characterized by solvent fractionation and thermogravimetric analysis (TGA). The cured ENR products are blended with PLA resin, by varying the cured ENR contents from 5 to 15% wt. Mechanical properties of the blends, and their toughening mechanisms are examined. The cured ENR materials has higher efficiency in improving toughness of PLA resin, compared to uncured ENR, likely due to their rubbery network nature and higher compatibility with the PLA matrix. The incorporation of 5% wt. GPLA-cured ENR also improves elongation at break with no adverse effect on tensile strength and modulus of PLA.

2019 ◽  
Vol 891 ◽  
pp. 163-168
Author(s):  
Kantima Chaochanchaikul

TThe aims of this research work were to improve touhgness and water resistance of wheat gluten (WG) by epoxidized natural rubber (ENR) compared to glycerol. WG specimens were mixed and prepared by internal mixer and compression molding machine, respectively. ENR and glycerol were varied from 10 to 40 wt%. Effects of modifier types and contents on WG were evaluated by tensile, impact and water absorption testings and microstructure and thermal analyses. The increase of ENR or glycerol contents led to the increase of toughness by considering the increase of impact strength and elongation at break. Glass transition temperature of WG tended to decrease with the increase of ENR or glycerol contents, especially for glycerol. The presence of glycerol affected to the decomposition temperature values whereas ENR did not affect to decomposition. ENR improved water resistant of WG specimen but trend of glycerol showed the opposite behavior. Weight loss of modified WG with glycerol was found at immersion time of 1440 min.


2012 ◽  
Vol 602-604 ◽  
pp. 690-695
Author(s):  
Hua Dong Wang ◽  
Rui Wang ◽  
Mao Fang Huang ◽  
Qi Yang

Thermoplastic vulcanizates (TPVs) based on epoxidized natural rubber (ENR) and polypropylene (PP) were prepared in an internal mixer at 180°C. The effects of curing systems (i.e., sulfur and peroxide) on morphological, rheological, thermal and mechanical properties were studied. It is found that the sulfur cured TPVs show higher tensile strength, tear strength and elongation at break than those cured with the DCP systems. The rheological analysis indicates that TPVs cured with DCP system show lower apparent shear viscosity than those with sulfur system. SEM studies show that TPVs vulcanized with DCP system exhibit smaller and finely dispersed rubber domains, which provides it higher thermal stability than sulfur cured TPVs.


2012 ◽  
Vol 626 ◽  
pp. 79-84
Author(s):  
Piriyapol Yokkhun ◽  
Bencha Thongnuanchan ◽  
Charoen Nakason

The present study focused on investigating the cure characteristics and mechanical properties of nanocomposites based on epoxidized natural rubber with 30 mol% epoxide (ENR-30)/nanoclay. ENR-30 based nanocomposites were prepared by melt compounding in an internal mixer and cured using a conventional sulphuric system. Two types of nanoclays were used in this study, sodium montmorillonite (Na-MMT) clay and Na-MMT that had been modified with octadecylamine, also referred to as OC-MMT. Overall results show that OC-MMT was more efficient in enhancing the mechanical properties of the ENR-30 nanocomposite than Na-MMT. This was probably attributed to the higher interlayer distance of OC-MMT, which was confirmed by X-ray diffraction results. The incorporation of OC-MMT into ENR-30 led to an increase in both the maximum torque (MH) and torque difference (MH-ML), which suggested an increase in the stiffness and crosslink density of the nanocomposite, respectively. A pronounced improvement in the tensile strength of the ENR-30/OC-MMT nanocomposite as compared to the unfilled ENR-30 was observed at 5 phr of OC-MMT, which appeared to be an optimum loading level. However, a gradual reduction in the elongation at break was observed with increasing OC-MMT loading.


2014 ◽  
Vol 48 (2) ◽  
pp. 105-121 ◽  
Author(s):  
Phrutsadee Sukpuang ◽  
Mantana Opaprakasit ◽  
Atitsa Petchsuk ◽  
Pramuan Tangboriboonrat ◽  
Punchapat Sojikul ◽  
...  

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Thanh Dung Ngo ◽  
Thi My Hanh Le ◽  
The Huu Nguyen ◽  
Thien Vuong Nguyen ◽  
Tuan Anh Nguyen ◽  
...  

For the vulcanized natural rubber (NR), incorporation of silver nanoparticles (AgNPs) into the NR matrix did not exhibit the bactericidal property against Escherichia coli (E. coli). However, incorporation of AgNPs into polyethylene (PE) matrix showed good antibacterial activities to both Gram-negative and Gram-positive bacteria. In the present work, NR/PE (85/15) blends have been prepared by melt blending with presence of compatibilizer in an internal mixer. To possess antibacterial property, AgNPs (5–10 nm) or Fe3O4–Ag hybrid nanoparticles (FAgNPs, 8 nm/16 nm) were added into PE matrix before its blending with NR component. The tensile test indicated that the presence of compatibilizer in NR/PE blend significantly enhanced the tensile strength and elongation at break (up to 35% and 38% increases, resp.). The antibacterial activity test was performed by monitoring of the bacterial lag-log growth phases with the presence of nanocomposites in the E. coli cell culture reactor. The antibacterial test showed that the presence of FAgNPs in NR/PE blend had a better antibacterial activity than that obtained with the lone AgNPs. Two similar reasons were proposed: (i) the faster Ag+ release rate from the Fe3O4–Ag hybrid nanoparticles due to the electron transfer from AgNP to Fe3O4 nanoparticle and (ii) the fact that the ionization of AgNPs in hybrid nanostructure might be accelerated by Fe3+ ions.


2014 ◽  
Vol 983 ◽  
pp. 342-346
Author(s):  
Tarinee Nampitch

Nowadays the use of biodegradable plastic in the food industry has increased dramatically. Because of its outstanding characteristics, i.e. environmental friendliness and non-toxicity, researchers are interested in studying how to improve the properties of plastic, especially polylactic acid or PLA, which is very fragile and intolerant to high impact force. Attempts have been made to improve the weak points of PLA by mixing PLA with epoxidized natural rubber. The natural rubber goes through an epoxidation process, resulting in epoxidized natural rubber (ENR) as the finished product. ENR contains epoxy groups which can efficiently react with PLA. Ratios of PLA and ENR employed in this study were 50:50, 60:40, 70:30, 80:20 and 90:10. In addition to finding a suitable ratio between PLA and ENR, the mixtures were subjected to migration tests according to the guidelines specified in European Commission Regulation (EU) No 10/2011 in order to prove whether the mixed materials are safe and suitable for consumer use. Migration testing was conducted by soaking samples in four different food simulants – 10% (v/v) ethanol in aqueous solution, 3% (w/v) acetic acid in aqueous solution, 20% (v/v) ethanol in aqueous solution and vegetable oil – for 24 h at 40 °C. The results showed that the PLA/ENR blends at every ratio had an overall migration amount of less than 10 mg/dm2 in three of the sample simulants, while the overall migration from materials soaked in vegetable oil exceeded this standard. Migration tests of one of the sample blends conducted at 100 °C for 2 h showed similar results. In conclusion, polymer blends of PLA and ENR are appropriate for food packaging applications, but are not appropriate for foods containing vegetable oil.


2013 ◽  
Vol 844 ◽  
pp. 109-112 ◽  
Author(s):  
Chesidi Hayichelaeh ◽  
Charoen Nakason ◽  
Anoma Thitithammawong

Epoxidized natural rubber (ENR)/Polypropylene (PP) thermoplastic vulcanizates were prepared by melt mixing method in an internal mixer. Influences of different mixing methods for incorporation of processing oil into the TPVs on tensile and dynamic mechanical properties of the TPVs and crystallinity of the PP were investigated. Results show that distribution of processing oil in the ENR/PP TPV is important due to the processing oil can promote and in the same time can interrupt an improvement in elastomeric properties of the TPV. Incorporation of processing oil into the ENR phase by preparation of oil extended ENR (the mixing method 1) before mixing with the PP was the better way to produce the TPV. It promoted the TPV with superior tensile and dynamic mechanical properties than the TPVs prepared from the mixing method 2 and 3 in which the processing oil was directly added into the PP phase. Furthermore, the TPV from the mixing method 1 had less effect of processing oil on the PP crystallization.


2011 ◽  
Vol 364 ◽  
pp. 427-433 ◽  
Author(s):  
Mohamad Yatim Norazlina ◽  
Yusof Faridah ◽  
Chantara Thevy Ratnam ◽  
Iis Sopyan

The effect of irradiation on the mechanical properties of Epoxidized Natural Rubber/Ethylene Vinyl Acetate/Carbon Nanotubes (ENR/EVA/CNTs) nanocomposites were investigated. CNTs at various amount (2, 3, 4 and 6 wt%) were incorporated into ENR50 by solvent casting method. The ENR/CNTs were then blended with EVA by mixing in a Brabender Plasticoder at 120°C. Next, the samples were irradiated by using electron beam with 3 MeV electron beam machine in a dose range of 50 to 200 kGy. The mechanical properties such as tensile strength (Ts), modulus at 100% elongation (M100), elongation at break (Eb) and hardness of reinforced ENR/EVA/CNTs nanocomposites were studied as a function of radiation dose. It was found that, the Ts and M100 has increased almost 2 times compared to the nanocomposites without irradiation up to 150 kGy dose of radiation, and a downward trend thereafter. Gel fraction further confirmed the powerful energy of electron beam radiation result in irradiation-induced crosslinking and further enhanced mechanical properties of the nanocomposites.


2019 ◽  
Vol 36 (1) ◽  
pp. 63-77 ◽  
Author(s):  
Ajaman Adair ◽  
Azizon Kaesaman ◽  
Pairote Klinpituksa

Epoxidized natural rubber (ENR) and a superabsorbent polymer composite (SAPC) along with other minor components were mechanically blended in an internal mixer (Brabender Plasticorder) at 40°C and 60 r/min rotor speed with 80% fill factor. The SAPC was synthesized by grafting polyacrylamide onto hydroxyethyl cellulose backbones and adding bentonite clay. The first water-swelling behavior was investigated with alternative epoxidation levels of the ENR. Water-swellable rubber (WSR) performed well in terms of water absorbency, and weight loss was achieved with 50 mole% epoxidation level, so this ENR was chosen for the rubber matrix from which WSR was prepared with various contents of SAPC (0, 5, 10, 15, and 20 phr). The results indicated that SAPC loading positively affected water absorbency, which was resulted by increasing weight loss and loss of mechanical properties, such as tensile strength and elongation at break. However, the modulus increased with SAPC content. WSR formulated from ENR-50, SAPC, and other ingredients resulting in good water-swelling behaviors and modulus, while the tensile strength and elongation at break had opposition. SAPC was an important factor to control the overall WSR properties.


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