Improving the properties of recycled PET/PEN blends by using different chain extenders

2016 ◽  
Vol 36 (6) ◽  
pp. 615-624 ◽  
Author(s):  
Simge Can ◽  
N. Gamze Karsli ◽  
Sertan Yesil ◽  
Ayse Aytac

Abstract The main aim of this study was to improve the mechanical properties of the recycled poly(ethylene terephthalate)/poly(ethylene 2,6-naphthalate) (r-PET/PEN) blends by enhancing the miscibility between PET and PEN with the usage of chain extenders. This idea was novel for the recycled PET-based r-PET/PEN blends, as investigation of the effects of the chain extender usage on the properties of r-PET/PEN blends has not been studied in the literature, according to our knowledge. 1,4-Phenylene-bis-oxazoline (PBO), 1,4-phenylene-di-isocyanate (PDI), and triphenyl phosphite (TPP) were selected as chain extenders. The maximum tensile strength value was observed for the 1.0PDI sample. Moreover, PDI-based blends exhibited better Izod impact strength when compared with all other samples. The miscibility and degree of crystallinity values of all blends were discussed by means of thermal analysis. 1H-nuclear magnetic resonance (1H-NMR) analysis was carried out to determine transesterification reaction levels. According to 1H-NMR results, the increase in the level of transesterification was around 40% with the usage of PDI. The optimum loading level for selected chain extenders was determined as 1 wt.%, and PDI-based blends exhibited better properties when compared with those of the blends based on PBO and TPP at this loading level.

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.


2011 ◽  
Vol 391-392 ◽  
pp. 688-691 ◽  
Author(s):  
Ming Yi Wang ◽  
Zhi Qiang Guo ◽  
Bu Yu Lei ◽  
Nan Qiao Zhou

In this work pyromellitic dianhydride (PMDA) was used as the chain extender to increase the molecular weight of the recycled poly(ethylene terephthalate) (R-PET) and improve the rheological properties of the R-PET. The reaction was performed in a Brabender torque rheometer. The rheological and thermal characterization were performed by means of a fusion index instrument and a differential scanning calorimeter (DSC ) to compare the effectiveness of the chain extending reaction of different percentages of PMDA. The experimental results showed that compared with the unmodified R-PET, the addition of PMDA decreased the melt flow index and increased the viscosity of the R-PET. In addition, increased crystallization temperatures ( ) were observed with the modified R-PET. It was also found that the modified R-PET with the concentration of 1.0wt% PMDA exhibited the lowest MFI.


2018 ◽  
Vol 772 ◽  
pp. 33-37
Author(s):  
Nattakarn Hongsriphan ◽  
Pajaera Patanathabutr ◽  
Kanyakarn Lappokachai

Recycled poly (ethylene terephthalate) or R-PET is conventionally melt blended with polycarbonate with the presence of chain extender in order to produce polymer blend that provides good mechanical properties and cost effectiveness. This research was carried out to improve properties of such a blend by compounding them with silane treated hollow glass microspheres (HGMs), which mixing procedure was emphasized how it could affect mechanical properties. R-PET/PC/HGM composites of a fixed composition were melt compounded with three different mixing procedures. It was found that the compounding HGMs with PC and then R-PET obtained the most rigidity specimens than the all-in-one compounding or the compounding HGMs with R-PET and then PC. Silane treated HGMs were well distributed in the polymer matrix presenting good interfacial adhesion. However, the notched impact strength of all composites were inspected to be in the same range.


2007 ◽  
Vol 60 (3) ◽  
pp. 167 ◽  
Author(s):  
Qin Zheng ◽  
Shuling Gong ◽  
Haiqing Dong ◽  
Yuanyin Chen

A series of polyether– or polyester–polyurethanes based on tetrahydrofuran–propylene oxide copolyether diol (PTMG/PPG) or poly(ethylene terephthalate) diol (PET), toluene diisocyanate (TDI), and three kinds of chain extenders including two calix[4]arene derivatives and 3,3´-dichloro-4,4´-diaminodiphenylmethane (MOCA) were synthesized in toluene. The thermal stability and mechanical properties of solvent-type polyurethanes were investigated. Incorporation of calixarenes into polyurethane backbones improved the thermal properties of the polyurethane as a result of the residual phenol hydroxy groups of the calix[4]arene units. Compared with polyurethane chain-extended by MOCA, the polyurethanes with calix[4]arene derivatives had higher elongation at break, lower elastic modulus, and lower yield strength, as a result of the larger steric cubage of calix[4]arene units and relatively large free volume of the polymer.


Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 236 ◽  
Author(s):  
Cuong N. Hoang ◽  
Chi T. Pham ◽  
Thu M. Dang ◽  
DongQuy Hoang ◽  
Pyoung-Chan Lee ◽  
...  

Rigid polyurethane foam (PUF) was successfully prepared from a novel oligo-ester-ether-diol obtained from the glycolysis of waste poly(ethylene terephthalate) (PET) bottles via reaction with diethylene glycol (DEG) in the presence of ZnSO4 7H2O. The LC-MS analysis of the oligodiol enabled us to identify 67 chemical homologous structures that were composed of zero to four terephthalate (T) ester units and two to twelve monoethylene glycol (M) ether units. The flame retardant, morphological, compression, and thermal properties of rigid PUFs with and without triphenyl phosphate (TPP) were determined. The Tg values showed that TPP played a role of not only being a flame retardant, but also a plasticizer. PUF with a rather low TPP loading had an excellent flame retardancy and high thermal stability. A loading of 10 wt % TPP not only achieved a UL-94 V-0 rating, but also obtained an LOI value of 21%. Meanwhile, the PUF without a flame retardant did not achieve a UL-94 HB rating; the sample completely burned to the holder clamp and yielded a low LOI value (17%). The fire properties measured with the cone calorimeter were also discussed, and the results further proved that the flame retardancy of the PUF with the addition of TPP was improved significantly. The polymeric material meets the demands of density and compression strength for commercial PUF, as well as the needs of environmental development. The current study may help overcome the drawback of intrinsic high flammability and enlarge the fire safety applications of materials with a high percentage of recycled PET.


1993 ◽  
Vol 321 ◽  
Author(s):  
Veronika E. Reinsch ◽  
Ludwig Rebenfeld

ABSTRACTBlends of poly (ethylene terephthalate), or PET, and polycarbonate (PC) over a range of compositions were studied in isothermal crystallizations from the melt using differential scanning calorimetry (DSC). Both crystallization rate and degree of crystallinity of PET depend on blend composition. The glass transition temperature, Tg, of PET and PC in blends and pure polymer were also measured by DSC. Elevation of the Tg of PET and depression of the Tg of PC are observed upon blending. In cooling scans, dynamic crystallization from the melt was observed. In PET/PC blends with high PC content, a novel dual-peak crystallization of PET was observed. The effects of thermal history on crystallization kinetics and degree of crystallinity were also determined in isothermal crystallization studies. For Melt processing times between 1 and 30 Min and for processing temperatures between 280 and 300 °C, Melt processing temperature was seen to have a stronger effect than processing time.


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