scholarly journals Poly (Lactic Acid)/Ground Tire Rubber Blends Using Peroxide Vulcanization

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1496
Author(s):  
Nicolas Candau ◽  
Oguzhan Oguz ◽  
Noel León Albiter ◽  
Gero Förster ◽  
Maria Lluïsa Maspoch

Poly (Lactic Acid) (PLA)/Ground Tire Rubber (GTR) blends using Dicumyl peroxide (DCP) as a crosslinking agent were prepared with the following aims: propose a new route to recycle wastes rubber from the automotive industry and improve the toughness and impact strength of the inherently brittle bio-based PLA. The GTR were subjected to two types of grinding process (cryo- and dry ambient grinding). Swelling measurements revealed the grinding to be associated with a mechanical damage of the rubber chains, independently on the type of grinding or on the GTR size (from <400 µm to <63 µm). Moreover, the finest GTR contains the largest amount of reinforcing elements (carbon black, clay) that can be advantageously used in PLA/GTR blends. Indeed, the use of the finest cryo-grinded GTR in the presence of DCP showed the least decrease of the tensile strength (−30%); maintenance of the tensile modulus and the largest improvement of the strain at break (+80%), energy at break (+60%) and impact strength (+90%) as compared to the neat PLA. The results were attributed to the good dispersion of both fine GTR and clay particles into the PLA matrix. Moreover, a possible re-crosslinking of the GTR particles and/or co-crosslinking at PLA/GTR interface in presence of DCP is expected to contribute to such improved ductility and impact strength.

Author(s):  
Nicolas Candau ◽  
Oguzhan Oguz ◽  
Noel León Albiter ◽  
Gero Förster ◽  
Maria Lluïsa Maspoch

Poly (Lactic Acid) (PLA) / Ground Tire Rubber (GTR) blends using Dicumyl peroxide (DCP) as a crosslinking agent were prepared as a route to recycle wastes rubber from the automotive industry. The GTR were exposed to grinding and exhibited mechanical damage, traduced at the rubber network scale by chains scission and/or chemical cross-links breakage. Such damage is accompanied by a decrease of 80% of the rubber chains network density of the initial tire buffing but found independent on the type of grinding (cryogenic, dry ambient) or on the GTR size (from &lt;400 &micro;m to &lt;63 &micro;m). Moreover, the finest sieved GTR contain the largest the amount of reinforcing elements (carbon black, clay) that can be advantageously used in PLA/GTR blends. The melt-blending of these finest GTR particles obtained by cryo-grinding at an amount of 15 wt.% and in presence of the crosslinking agent (DCP), resulted in an optimum improvement of the ductility, energy at break and impact strength of the PLA/GTR blends as compared to neat PLA, while maintaining its stiffness. The results were attributed to (i) the good dispersion of the fine GTR particles into the PLA matrix, (ii) the partial re-crosslinking of the GTR particles and co-crosslinking at PLA/GTR interface and (iii) the presence of reinforcing carbon black into the GTR particles and clay particles dispersed into the PLA matrix.


2014 ◽  
Vol 970 ◽  
pp. 312-316
Author(s):  
Sujaree Tachaphiboonsap ◽  
Kasama Jarukumjorn

Thermoplastic starch (TPS)/poly (lactic acid) (PLA) blend and thermoplastic starch (TPS)/poly (lactic acid) (PLA)/poly (butylene adipate-co-terephthalate) (PBAT) blend were prepared by melt blending method. PLA grafted with maleic anhydride (PLA-g-MA) was used as a compatibilizer to improve the compatibility of the blends. As TPS was incorporated into PLA, elongation at break was increased while tensile strength, tensile modulus, and impact strength were decreased. Tensile properties and impact properties of TPS/PLA blend were improved with adding PLA-g-MA indicating the enhancement of interfacial adhesion between PLA and TPS. With increasing PBAT content, elongation at break and impact strength of TPS/PLA blends were improved. The addition of TPS decreased glass transition temperature (Tg), crystallization temperature (Tc), and melting temperature (Tm) of PLA. Tgand Tcof TPS/PLA blend were decreased by incorporating PLA-g-MA. However, the presence of PBAT reduced Tcof TPS/PLA blend. Thermal properties of TPS/PLA/PBAT blends did not change with increasing PBAT content. SEM micrographs revealed that the compatibilized TPS/PLA blends exhibited finer morphology when compared to the uncompatibilized TPS/PLA blend.


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Wei Kit Chee ◽  
Nor Azowa Ibrahim ◽  
Norhazlin Zainuddin ◽  
Mohd Faizal Abd Rahman ◽  
Buong Woei Chieng

Poly(lactic acid) (PLA)/poly(ε-caprolactone) (PCL) blends were prepared via melt blending technique. Glycidyl methacrylate (GMA) was added as reactive compatibilizer to improve the interfacial adhesion between immiscible phases of PLA and PCL matrices. Tensile test revealed that optimum in elongation at break of approximately 327% achieved when GMA loading was up to 3wt%. Slight drop in tensile strength and tensile modulus at optimum ratio suggested that the blends were tuned to be deformable. Flexural studies showed slight drop in flexural strength and modulus when GMA wt% increases as a result of improved flexibility by finer dispersion of PCL in PLA matrix. Besides, incorporation of GMA in the blends remarkably improved the impact strength. Highest impact strength was achieved (160% compared to pure PLA/PCL blend) when GMA loading was up to 3 wt%. SEM analysis revealed improved interfacial adhesion between PLA/PCL blends in the presence of GMA. Finer dispersion and smooth surface of the specimens were noted as GMA loading increases, indicating that addition of GMA eventually improved the interfacial compatibility of the nonmiscible blend.


2018 ◽  
Vol 14 (3) ◽  
pp. 348-352 ◽  
Author(s):  
Nur Amira Sahirah Abdullah ◽  
Zurina Mohamad

Poly (lactic acid)/epoxidized natural rubber (PLA/ENR) was prepared by using counter-rotating twin-screw extruder. For dynamic vulcanization process, ENR was compounded with 3 phr of N, N’-m-phenylenebismaleimide (HVA-2) as a crosslinking agent. The aim of this study is to determine the effect of unvulcanized and dynamically vulcanized of ENR on the properties of PLA/ENR blend. The blending of PLA with ENR was prepared with the various composition of ENR (0 wt% to 30 wt%). The morphology and mechanical properties of the blends were investigated by using scanning electron microscope (SEM), tensile test, and impact test. The unvulcanized blend produced a co-continuous morphology of PLA and ENR and the dynamically vulcanized blend shows the dispersed ENR rubber particles in PLA continuous matrix.  For both systems, the tensile strength value was dropped with the increasing amount of ENR content. The impact strength of both systems shows the maximum value at 20 wt% of ENR content. However, dynamically vulcanized PLA/ENR blend shows a better tensile strength and impact strength value as compared with unvulcanized blend.


2015 ◽  
Vol 1125 ◽  
pp. 222-226 ◽  
Author(s):  
Mohd Shaiful Zaidi Mat Desa ◽  
Azman Hassan ◽  
Agus Arsad ◽  
Nor Nisa Balqis Mohammad

The effect of rubber toughening on mechanical and thermal properties of poly (lactic acid) (PLA) was investigated by using three types of rubbers; natural rubber (NR), epoxidized natural rubber (ENR) and core-shell rubber (CSR). The PLA/rubber blends were prepared by melt blending in a counter-rotating twin-screw extruder, where the rubber content for all blends was kept at 5 wt%. It was found that the addition of the rubbers increased the impact strength for all blends as compared to pure PLA. On the other hand, all PLA/rubber blends showed notable decrease of Young’s modulus especially for PLA/NR blend which decreased by 72% than pure PLA. Similarly, significant decrease of tensile strength was also observed for all PLA/rubber blends. PLA/ENR blend showed a morebalance mechanical properties with fairly significant improvement of impact strength and moderate decrease of tensile strength, Young’s modulus and elongation at break. In general, PLA/NR blend showed the highest overall impact strength, while the PLA/CSR showed the highest tensile strength and Young’s modulus among the blends. Thermal analysis revealed that the Tg of PLA decreased with incorporation of the three types of rubbers with NR showing the largest decrease. This study indicates that NR, ENR and CSR are effective in enhancing toughness of PLA


2019 ◽  
Vol 821 ◽  
pp. 89-95
Author(s):  
Wanasorn Somphol ◽  
Thipjak Na Lampang ◽  
Paweena Prapainainar ◽  
Pongdhorn Sae-Oui ◽  
Surapich Loykulnant ◽  
...  

Poly (lactic acid) or PLA was reinforced by nanocellulose and polyethylene glycol (PEG), which were introduced into PLA matrix from 0 to 3 wt.% to enhance compatibility and strength of the PLA. The nanocellulose was prepared by TEMPO-mediated oxidation from microcrystalline cellulose (MCC) powder and characterized by TEM, AFM, and XRD to reveal rod-like shaped nanocellulose with nanosized dimensions, high aspect ratio and high crystallinity. Films of nanocellulose/PEG/PLA nanocomposites were prepared by solvent casting method to evaluate the mechanical performance. It was found that the addition of PEG in nanocellulose-containing PLA films resulted in an increase in tensile modulus with only 1 wt% of PEG, where higher PEG concentrations negatively impacted the tensile strength. Furthermore, the tensile strength and modulus of nanocellulose/PEG/PLA nanocomposites were higher than the PLA/PEG composites due to the existence of nanocellulose chains. Visual traces of crazing were detailed to describe the deformation mechanism.


Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3234
Author(s):  
Wangwang Yu ◽  
Lili Dong ◽  
Wen Lei ◽  
Yuhan Zhou ◽  
Yongzhe Pu ◽  
...  

To develop a new kind of environment-friendly composite filament for fused deposition modeling (FDM) 3D printing, rice straw powder (RSP)/poly(lactic acid) (PLA) biocomposites were FDM-3D-printed, and the effects of the particle size and pretreatment of RSP on the properties of RSP/PLA biocomposites were investigated. The results indicated that the 120-mesh RSP/PLA biocomposites (named 120#RSP/PLA) showed better performance than RSP/PLA biocomposites prepared with other RSP sizes. Infrared results showed that pretreatment of RSP by different methods was successful, and scanning electron microscopy indicated that composites prepared after pretreatment exhibited good interfacial compatibility due to a preferable binding force between fiber and matrix. When RSP was synergistically pretreated by alkaline and ultrasound, the composite exhibited a high tensile strength, tensile modulus, flexural strength, and flexural modulus of 58.59, 568.68, 90.32, and 3218.12 MPa, respectively, reflecting an increase of 31.19%, 16.48%, 18.75%, and 25.27%, respectively, compared with unmodified 120#RSP/PLA. Pretreatment of RSP also improved the thermal stability and hydrophobic properties, while reducing the water absorption of 120#RSP/PLA. This work is believed to provide highlights of the development of cost-effective biocomposite filaments and improvement of the properties of FDM parts.


2012 ◽  
Vol 27 (4) ◽  
pp. 427-433 ◽  
Author(s):  
X. Zhang ◽  
Z. Zhou ◽  
X. He ◽  
J. Li ◽  
C. Lu

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