scholarly journals Poly(ethylene terephthalate) Powder—A Versatile Material for Additive Manufacturing

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2041 ◽  
Author(s):  
Hao Gu ◽  
Fayez AlFayez ◽  
Toseef Ahmed ◽  
Zahir Bashir

The 3D printing of articles by the effect of a directed laser beam on a plastic powder is a demanding process, and unlike injection molding, very few polymers work well enough with it. Recently, we reported that poly(ethylene terephthalate) (PET) powder has intrinsically good properties for 3D printing. Basic mechanical properties were shown earlier and it was demonstrated that unfused but heat-exposed PET powder does not degrade quickly allowing good re-use potential. In this work, we conducted a detailed comparison of the mechanical properties of PET and polyamide 12 from different build orientations. PET powders with two different molecular weights were used. With the high molecular weight powder, the processing parameters were optimized, and the printed bars showed little difference between the different orientations, which means there is low anisotropy in mechanical properties of built parts. Based on processing experience of the first powder, the second powder with a lower molecular weight was also very printable and complex parts were made with ease from the initial printing trials; since the process parameters were not optimized then, lower mechanical properties were obtained. While the intrinsic material properties of PET (melting and re-crystallization kinetics) are not the best for injection molding, PET is eminently suitable for powder bed fusion.

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Jian Min Zhang ◽  
Qingsong Hua ◽  
Christopher T. Reynolds ◽  
Yuling Zhao ◽  
Zuoqiang Dai ◽  
...  

Poly(ethylene terephthalate) (PET) which is one of the most commercially important polymers, has for many years been an interesting candidate for the production of high performance fibres and tapes. In current study, we focus on investigating the effects of the various processing variables on the mechanical properties of PET produced by a distinctive process of melt spinning and uniaxial two-stage solid-state drawing (SSD). These processing variables include screw rotation speed during extrusion, fibre take-up speed, molecular weight, draw-ratio, and drawing temperature. As-spun PET production using a single-screw extrusion process was first optimized to induce an optimal polymer microstructure for subsequent drawing processes. It was found that less crystallization which occurred during this process would lead to better drawability, higher draw-ratio, and mechanical properties in the subsequent SSD process. Then the effect of drawing temperature (DT) in uniaxial two-stage SSD process was studied to understand how DT (<Tg or close to Tg or close to Trec) would affect the crystallization, draw-ratio, and final mechanical properties of PET. The designed process in current work is simulated to an industrial production process for PET fibres; therefore, results and analysis in this paper have significant importance for industrial production.


2014 ◽  
Vol 34 (1) ◽  
pp. 5-13 ◽  
Author(s):  
Yottha Srithep ◽  
Lih-Sheng Turng

Abstract Poly(ethylene terephthalate) (PET) resin is one of the most widely used thermoplastics, especially in packaging. Due to thermal and hydrolytic degradations, recycled PET (RPET) exhibits poor mechanical properties and lacks moldability. The effects of adding chain extender (CE) and nanoclay to RPET were investigated. Melt blending of RPET with CE was performed in a thermokinetic mixer (K-mixer). The blended materials were then prepared via solid and microcellular injection molding processes. The effects of CE loading levels and the simultaneous addition of nanoclay on the thermal and mechanical properties and cell morphology of the microcellular components were noted. The addition of 1.3% CE enhanced the tensile properties and viscosity of RPET. The higher amount of CE (at 3%) enhanced the viscosity, but the margin of improvement in mechanical properties diminished. While the solid RPET and CE blends were fairly ductile, the samples with nanoclay and all microcellular specimens showed brittle fractural behavior. Finally, nanoclay and the increase of CE content decreased the average cell size and enlarged the cell density of the microcellular samples.


2017 ◽  
Vol 37 (3) ◽  
pp. 271-277 ◽  
Author(s):  
Takanori Negoro ◽  
Rutchaneekorn Wongpajan ◽  
Wiranphat Thodsaratpreeyakul ◽  
Jitlada Boonlertsamut ◽  
Supaphorn Thumsorn ◽  
...  

Abstract Blending of recycled poly(ethylene terephthalate) (RPET) and polycarbonate (PC) was performed by melt compounding. The blends were subsequently fabricated to dumbbell specimens by vented injection molding. The mechanical properties, thermal characteristic and morphology of RPET/PC blends were investigated as a function of PC contents. Vented injection molding presented an advantage for superior mechanical properties of RPET/PC blends. The addition of PC enhanced impact strength and fracture toughness with remaining tensile properties. The glass transition temperatures of PET and PC shifted toward each other, which indicated their partial miscibility of RPET and PC in the blends. The toughness mechanism of RPET and PC was related to core-shell structure and good interfacial adhesion at higher contents of PC.


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