In this research, recycled-polyethylene terephthalate (PET) and polycarbonate (RPET/PC) blends fabricated by vented barrel injection molding were presented to better understand the effect of devolatilization during mo...In this research, recycled-polyethylene terephthalate (PET) and polycarbonate (RPET/PC) blends fabricated by vented barrel injection molding were presented to better understand the effect of devolatilization during molding process. The effect of dried pellets, non-dried pellets, using an opened-vented hole, and using a closed-vented hole on the miscibility, morphology, thermal properties and mechanical properties of RPET/PC blends was investigated. The results indicated that no drying decreases dispersion, thermal properties, and mechanical properties of RPET/PC blends due to hydrolysis degradation of recycled-PET during the injection molding process. Using the venting system with non-dried RPET/PC blends partially improves dispersion, thermal properties and molecular weight of RPET/PC blends processed without drying, giving results that are similar to those processed with drying. Regarding the flexural properties, using the venting system without drying prevents the flexural properties from decreasing in RPET/PC blends, if the amount of RPET is less than 75 wt%. When the content of RPET is over 75 wt%, using the venting system does not eliminate the decrease in flexural properties of RPET/PC blends. When the venting system is applied to non-dried RPET, despite hydrolysis degradation of RPET not being completely eliminated, the damaging effects are nonetheless reduced compared with those samples processed without the venting system. As a result, vented barrel injection molding hardly prevents non-dried RPET/PC blends from having reduced flexural properties when the content of RPET is greater than 75 wt%.展开更多
The chrysotile asbestos was converted to the forsterite-type compounds by calcination at 740 and 800oC (F7-740 and F7-800), which were used as a catalyst for the polycondensation of bis(hydroxyethyl) terephthalate aff...The chrysotile asbestos was converted to the forsterite-type compounds by calcination at 740 and 800oC (F7-740 and F7-800), which were used as a catalyst for the polycondensation of bis(hydroxyethyl) terephthalate affording poly (ethylene terephthalate). The obtained forsterite-type compounds did not show any catalytic activity. However, the products obtained by simply treating them with acetic acid significantly promoted the polymerization that produced a THFinsoluble polymer. It was found that the polymer prepared with the acetic acid-treated F7-740 at 160oC for 2 h showed a 93% yield and the number average molecular weight of 6.4 × 103. The observed catalytic activity was higher than that for the acetic acid-treated magnesium oxide, as well as the typical polycondensation catalysts, such as magnesium acetate and antimony oxide.展开更多
This article deals with the study of the viscoelastic and thermal properties of polyurethane (PU) rigid foamsfrom biobased and recycled components. Rapeseed oil (RO) and recycled poly(ethylene terephthalate)(PET) were...This article deals with the study of the viscoelastic and thermal properties of polyurethane (PU) rigid foamsfrom biobased and recycled components. Rapeseed oil (RO) and recycled poly(ethylene terephthalate)(PET) were used to synthesize PU polyols. Addition of adipic acid (ADA) to polyol resulted in improvedthermal and viscoelastic properties of foam materials. ADA content was varied from 1 to 6 wt%. Results ofthe dynamic mechanical spectra indicate an increase of the storage modulus E′ and the loss modulus E″ inthe whole temperature range for specimens with higher loading of ADA. In addition, damping factor shiftedto higher temperatures, but damping intensity remained almost unaffected by the compositions. Scanningelectron microscopy of the foams’ cross sections testified that the average cells’ size of 110 mm was unaffectedby the ADA content in polyol.展开更多
文摘In this research, recycled-polyethylene terephthalate (PET) and polycarbonate (RPET/PC) blends fabricated by vented barrel injection molding were presented to better understand the effect of devolatilization during molding process. The effect of dried pellets, non-dried pellets, using an opened-vented hole, and using a closed-vented hole on the miscibility, morphology, thermal properties and mechanical properties of RPET/PC blends was investigated. The results indicated that no drying decreases dispersion, thermal properties, and mechanical properties of RPET/PC blends due to hydrolysis degradation of recycled-PET during the injection molding process. Using the venting system with non-dried RPET/PC blends partially improves dispersion, thermal properties and molecular weight of RPET/PC blends processed without drying, giving results that are similar to those processed with drying. Regarding the flexural properties, using the venting system without drying prevents the flexural properties from decreasing in RPET/PC blends, if the amount of RPET is less than 75 wt%. When the content of RPET is over 75 wt%, using the venting system does not eliminate the decrease in flexural properties of RPET/PC blends. When the venting system is applied to non-dried RPET, despite hydrolysis degradation of RPET not being completely eliminated, the damaging effects are nonetheless reduced compared with those samples processed without the venting system. As a result, vented barrel injection molding hardly prevents non-dried RPET/PC blends from having reduced flexural properties when the content of RPET is greater than 75 wt%.
文摘The chrysotile asbestos was converted to the forsterite-type compounds by calcination at 740 and 800oC (F7-740 and F7-800), which were used as a catalyst for the polycondensation of bis(hydroxyethyl) terephthalate affording poly (ethylene terephthalate). The obtained forsterite-type compounds did not show any catalytic activity. However, the products obtained by simply treating them with acetic acid significantly promoted the polymerization that produced a THFinsoluble polymer. It was found that the polymer prepared with the acetic acid-treated F7-740 at 160oC for 2 h showed a 93% yield and the number average molecular weight of 6.4 × 103. The observed catalytic activity was higher than that for the acetic acid-treated magnesium oxide, as well as the typical polycondensation catalysts, such as magnesium acetate and antimony oxide.
文摘This article deals with the study of the viscoelastic and thermal properties of polyurethane (PU) rigid foamsfrom biobased and recycled components. Rapeseed oil (RO) and recycled poly(ethylene terephthalate)(PET) were used to synthesize PU polyols. Addition of adipic acid (ADA) to polyol resulted in improvedthermal and viscoelastic properties of foam materials. ADA content was varied from 1 to 6 wt%. Results ofthe dynamic mechanical spectra indicate an increase of the storage modulus E′ and the loss modulus E″ inthe whole temperature range for specimens with higher loading of ADA. In addition, damping factor shiftedto higher temperatures, but damping intensity remained almost unaffected by the compositions. Scanningelectron microscopy of the foams’ cross sections testified that the average cells’ size of 110 mm was unaffectedby the ADA content in polyol.
