Based on the premise that the addition of glass beads （GB） could hardly influence the linear viscoelasticity in low frequency （ω） region for homogeneous polymer systems, the dynamic rheological behaviors of unfil...Based on the premise that the addition of glass beads （GB） could hardly influence the linear viscoelasticity in low frequency （ω） region for homogeneous polymer systems, the dynamic rheological behaviors of unfilled and filled poly（methyl methyacrylate） （PMMA）/poly（styrene-co-acrylonitrile） （SAN） blends were studied in order to explore the effect of GB on the phase-separation of binary polymer matrix. Results show that GB has an induced effect on the phase-separation, which embodies that the phase-separation temperature （Ts） of PMMA/SAN blend filled with GB is lower than that of the unfilled system. The higher content of GB, the higher is the ＂secondary plateau＂ of ω in the terminal region of storage modulus （G＇） versus ω plot. The ＂secondary plateau＂ appearing in the terminal region is attributed to the phase-separation of PMMA/SAN blends and it becomes more fiat for filled polymer blends under the same conditions. However, it is suggested that this kind of ＂induced effect＂ is related to the GB content; the higher content of GB particles might enhance the interaction between the particles and polymer matrix. Moreover, it is found that the addition of GB also has an influence more or less on the morphology and domain size of polymer matrix. It is believed that the plot of dynamic viscosity （η＇） versus the loss viscosity （η＂） is sensitive to examine the effect induced by GB on the phase-separation of binary polymer matrix.展开更多
In this work, controlling of the particle size of PVC in PS/PVC blends was studied. It is shown that viscosity ratio and particle size can be changed by adding a third composition, such as plasticizers, and the distri...In this work, controlling of the particle size of PVC in PS/PVC blends was studied. It is shown that viscosity ratio and particle size can be changed by adding a third composition, such as plasticizers, and the distribution of the third composition in two phases plays a very important role in controlling viscosity ratio and particle size. When DOP was used as the plasticizer of PVC in PS/PVC blends, the particle size of PVC could not be reduced due to the transference of DOP into PS phase. When polycaprolactone (PCL) was used as the plasticizer of PVC in the same blends, the particle size of PVC could be descreased obviously because PCL does not migrate to PS phase.展开更多
The dynamic mechanical modulus at 25℃ for blends of segmented polyurethanes with PVC was studied by using suitable mechanics models of multi-component systems. The analysis indicates that the blend morphology was mai...The dynamic mechanical modulus at 25℃ for blends of segmented polyurethanes with PVC was studied by using suitable mechanics models of multi-component systems. The analysis indicates that the blend morphology was mainly determined by soft segment structure of polyurethanes. The PPO-PU/PVC blends show typical two-phase morphology and their modulus-composition relations may be described by Halpin-Tsai model for domain-matrix two-phase systems.While the PCL-PU / PVC, PTMA-PU/PVC and PTMO-PU/PVC blends fit the Kerner's packed grain composite model. These results may imply that the modulus-composition relationship is sensitive to the interactions between the components and the mixture morphology of the blends.展开更多
Film specimens of four segmented polyurethanes with different soft segments, namely polycaprolactone, polytetramethylene adipate, polytetramethylene oxide and polypropylene oxide, and their blends with PVC of differen...Film specimens of four segmented polyurethanes with different soft segments, namely polycaprolactone, polytetramethylene adipate, polytetramethylene oxide and polypropylene oxide, and their blends with PVC of different compositions were obtained by solution cast. The permeability of these films to O_2, N_2 and H_2 and their density were measured by using gas chromatography and technique of density gradient column. The polyether polyurethanes were found to have higher permeability than the polyester ones due to their low glass transition temperature and /or the low density value. The blends of PVC and polyether polyurethanes, especially the PPO-based polyurethane, are incompatible, and their permeability coefficient-composition dependence has the typical S-shaped curves. PVC is well compatible with the soft segments in its blends with polyester polyurethanes. For these blends the composition dependence of permeability is characterized by a negative deviation from the semilogarithmic additivity rule, and it is possible to prepare blends having T_g 20℃ lower than that of PVC, but retaining its low permeability almost unchanged, results were discussed in according with the different approaches for the permeation behavior of compatible and incompatible blends.展开更多
Series of PVC/ABS and PVC/SBS blends of composition 20/ 80. 40/ 60, 60 / 40 and 80 / 20were prepared in a screw extruder. The phase morphology, miscibility and rheological behaviour of two systems were investigated. T...Series of PVC/ABS and PVC/SBS blends of composition 20/ 80. 40/ 60, 60 / 40 and 80 / 20were prepared in a screw extruder. The phase morphology, miscibility and rheological behaviour of two systems were investigated. The viscosity-composition plots were represented by sub-cluster equation, the various differences between two systems are interpreted with the equation parameters展开更多
In this research, an attempt was made to improve compatibility in a polymer blend composed of incompatible constituents, namely, recycled polystyrene (rPS) and polystyrene-co-acrylonitrile (SAN), through the addition ...In this research, an attempt was made to improve compatibility in a polymer blend composed of incompatible constituents, namely, recycled polystyrene (rPS) and polystyrene-co-acrylonitrile (SAN), through the addition of a compatibilizer. The compatibilizing agent, styrene-ethylenebutadiene-styrene block copolymer (SEBS), was added to the polymer blend in ratios of 5 and 10 wt%. For this purpose, blends of rPS and SAN at different ratios, without and with varying concentrations of compatibilizer, were prepared by melt blending using a co-rotating twin-screwextruder. Mechanical properties including tensile and impact strength, rheological properties (RPA), thermal behaviour (DSC) and morphological characteristics (SEM) were evaluated. According to the results obtained by complex viscosity, the blends behave as a pseudoplastic fluid. The results showed that the addition of SEBS increased the Izod impact strength and the elongation at break and decreased the tensile strength and tensile modulus. rPS/SAN blend modified with SEBS had better mechanical properties than the rPS/SAN alloy. SEM photographs revealed that the SEBS was not only distributed in the SAN phase but also distributed in rPS phase in rPS/SAN/SEBS blend. Furthermore, DSC analysis for blends of rPS/SAN gave a good indication of the improvement on miscibility for most compositions. SEM micrographs of tensile fracture surfaces indicated that the formation of the co-continuous phase and the improvement of interface adhesion are the most important reasons for the excellent tensile properties of the rPS/SAN/SEBS blends. Within the range of analysed compositions, the morphologies investigated by SEM are typical of immiscible blends.展开更多
The mechanical and thermal properties of solution-cast blends of Polyvinyl chloride (PVC) and Epoxidized Liquid Natural Rubber having 30 mole % epoxidation (ELNR-30) have been examined using Zwick materials testing ma...The mechanical and thermal properties of solution-cast blends of Polyvinyl chloride (PVC) and Epoxidized Liquid Natural Rubber having 30 mole % epoxidation (ELNR-30) have been examined using Zwick materials testing machine and heating in air circulating oven (200°C) at different time intervals respectively. The ELNR was prepared by oxidative degradation of natural rubber latex using Phenylhydrazine/Oxygen system and subsequent epoxidation with formic acid and 30% H2O2. Tensile strength of unblended PVC was 26.5 ± 0.5 MPa. The blends had lower tensile strength which decreased with increase in blend ratio of ELNR-30. Experimental data revealed that there was greater homogeneity in the PVC/ELNR-30 (80/20) compared with PVC/ELNR-30 (90/10). The PVC/ELNR-30 (80/20) also showed superior elongation at maximum (%) than the unblended PVC and PVC/ELNR-30 (90/10) in that order. Thermal stability decreased in the order PVC, PVC/ELNR-30 (90/10), PVC/ELNR-30 (80/20).展开更多
Blend of natural rubber (NR) and chlorosulfonated polyethylene (CSM) was so interesting due to binding of the good oil resistance of CSM, the good mechanical properties and low cost of NR. However, due to the differen...Blend of natural rubber (NR) and chlorosulfonated polyethylene (CSM) was so interesting due to binding of the good oil resistance of CSM, the good mechanical properties and low cost of NR. However, due to the different polarities of two rubbers, phase separation and inferior properties of NR/CSM blend were obtained. The practical way to improve its properties is the addition of the third component to bind both phases of the blend. Effects of poly(vinyl chloride), PVC as compatibilizer on cure characteristics, morphology, mechanical properties and automotive fuel resistance of NR/ CSM blend were investigated. In this contribution, NR/CSM blend with blend ratio of 50/50 was prepared using a two-roll mill, and then vulcanized in a compression mold at 160°C. The PVC content was varied from 1 to 7 phr. It was found that the usage of 7 phr PVC led to improve interaction between NR and CSM phases. Therefore, increase in cure characteristics, mechanical strength and automotive fuel resistance of the blend was observed.展开更多
基金This project was supported by the National Natural Science Foundation of China(No.20304014)the Special Funds for National Science Funds for Distinguished Young Scholars(No.50125312).
文摘Based on the premise that the addition of glass beads （GB） could hardly influence the linear viscoelasticity in low frequency （ω） region for homogeneous polymer systems, the dynamic rheological behaviors of unfilled and filled poly（methyl methyacrylate） （PMMA）/poly（styrene-co-acrylonitrile） （SAN） blends were studied in order to explore the effect of GB on the phase-separation of binary polymer matrix. Results show that GB has an induced effect on the phase-separation, which embodies that the phase-separation temperature （Ts） of PMMA/SAN blend filled with GB is lower than that of the unfilled system. The higher content of GB, the higher is the ＂secondary plateau＂ of ω in the terminal region of storage modulus （G＇） versus ω plot. The ＂secondary plateau＂ appearing in the terminal region is attributed to the phase-separation of PMMA/SAN blends and it becomes more fiat for filled polymer blends under the same conditions. However, it is suggested that this kind of ＂induced effect＂ is related to the GB content; the higher content of GB particles might enhance the interaction between the particles and polymer matrix. Moreover, it is found that the addition of GB also has an influence more or less on the morphology and domain size of polymer matrix. It is believed that the plot of dynamic viscosity （η＇） versus the loss viscosity （η＂） is sensitive to examine the effect induced by GB on the phase-separation of binary polymer matrix.
文摘In this work, controlling of the particle size of PVC in PS/PVC blends was studied. It is shown that viscosity ratio and particle size can be changed by adding a third composition, such as plasticizers, and the distribution of the third composition in two phases plays a very important role in controlling viscosity ratio and particle size. When DOP was used as the plasticizer of PVC in PS/PVC blends, the particle size of PVC could not be reduced due to the transference of DOP into PS phase. When polycaprolactone (PCL) was used as the plasticizer of PVC in the same blends, the particle size of PVC could be descreased obviously because PCL does not migrate to PS phase.
文摘The dynamic mechanical modulus at 25℃ for blends of segmented polyurethanes with PVC was studied by using suitable mechanics models of multi-component systems. The analysis indicates that the blend morphology was mainly determined by soft segment structure of polyurethanes. The PPO-PU/PVC blends show typical two-phase morphology and their modulus-composition relations may be described by Halpin-Tsai model for domain-matrix two-phase systems.While the PCL-PU / PVC, PTMA-PU/PVC and PTMO-PU/PVC blends fit the Kerner's packed grain composite model. These results may imply that the modulus-composition relationship is sensitive to the interactions between the components and the mixture morphology of the blends.
文摘Film specimens of four segmented polyurethanes with different soft segments, namely polycaprolactone, polytetramethylene adipate, polytetramethylene oxide and polypropylene oxide, and their blends with PVC of different compositions were obtained by solution cast. The permeability of these films to O_2, N_2 and H_2 and their density were measured by using gas chromatography and technique of density gradient column. The polyether polyurethanes were found to have higher permeability than the polyester ones due to their low glass transition temperature and /or the low density value. The blends of PVC and polyether polyurethanes, especially the PPO-based polyurethane, are incompatible, and their permeability coefficient-composition dependence has the typical S-shaped curves. PVC is well compatible with the soft segments in its blends with polyester polyurethanes. For these blends the composition dependence of permeability is characterized by a negative deviation from the semilogarithmic additivity rule, and it is possible to prepare blends having T_g 20℃ lower than that of PVC, but retaining its low permeability almost unchanged, results were discussed in according with the different approaches for the permeation behavior of compatible and incompatible blends.
文摘Series of PVC/ABS and PVC/SBS blends of composition 20/ 80. 40/ 60, 60 / 40 and 80 / 20were prepared in a screw extruder. The phase morphology, miscibility and rheological behaviour of two systems were investigated. The viscosity-composition plots were represented by sub-cluster equation, the various differences between two systems are interpreted with the equation parameters
文摘In this research, an attempt was made to improve compatibility in a polymer blend composed of incompatible constituents, namely, recycled polystyrene (rPS) and polystyrene-co-acrylonitrile (SAN), through the addition of a compatibilizer. The compatibilizing agent, styrene-ethylenebutadiene-styrene block copolymer (SEBS), was added to the polymer blend in ratios of 5 and 10 wt%. For this purpose, blends of rPS and SAN at different ratios, without and with varying concentrations of compatibilizer, were prepared by melt blending using a co-rotating twin-screwextruder. Mechanical properties including tensile and impact strength, rheological properties (RPA), thermal behaviour (DSC) and morphological characteristics (SEM) were evaluated. According to the results obtained by complex viscosity, the blends behave as a pseudoplastic fluid. The results showed that the addition of SEBS increased the Izod impact strength and the elongation at break and decreased the tensile strength and tensile modulus. rPS/SAN blend modified with SEBS had better mechanical properties than the rPS/SAN alloy. SEM photographs revealed that the SEBS was not only distributed in the SAN phase but also distributed in rPS phase in rPS/SAN/SEBS blend. Furthermore, DSC analysis for blends of rPS/SAN gave a good indication of the improvement on miscibility for most compositions. SEM micrographs of tensile fracture surfaces indicated that the formation of the co-continuous phase and the improvement of interface adhesion are the most important reasons for the excellent tensile properties of the rPS/SAN/SEBS blends. Within the range of analysed compositions, the morphologies investigated by SEM are typical of immiscible blends.
文摘The mechanical and thermal properties of solution-cast blends of Polyvinyl chloride (PVC) and Epoxidized Liquid Natural Rubber having 30 mole % epoxidation (ELNR-30) have been examined using Zwick materials testing machine and heating in air circulating oven (200°C) at different time intervals respectively. The ELNR was prepared by oxidative degradation of natural rubber latex using Phenylhydrazine/Oxygen system and subsequent epoxidation with formic acid and 30% H2O2. Tensile strength of unblended PVC was 26.5 ± 0.5 MPa. The blends had lower tensile strength which decreased with increase in blend ratio of ELNR-30. Experimental data revealed that there was greater homogeneity in the PVC/ELNR-30 (80/20) compared with PVC/ELNR-30 (90/10). The PVC/ELNR-30 (80/20) also showed superior elongation at maximum (%) than the unblended PVC and PVC/ELNR-30 (90/10) in that order. Thermal stability decreased in the order PVC, PVC/ELNR-30 (90/10), PVC/ELNR-30 (80/20).
文摘Blend of natural rubber (NR) and chlorosulfonated polyethylene (CSM) was so interesting due to binding of the good oil resistance of CSM, the good mechanical properties and low cost of NR. However, due to the different polarities of two rubbers, phase separation and inferior properties of NR/CSM blend were obtained. The practical way to improve its properties is the addition of the third component to bind both phases of the blend. Effects of poly(vinyl chloride), PVC as compatibilizer on cure characteristics, morphology, mechanical properties and automotive fuel resistance of NR/ CSM blend were investigated. In this contribution, NR/CSM blend with blend ratio of 50/50 was prepared using a two-roll mill, and then vulcanized in a compression mold at 160°C. The PVC content was varied from 1 to 7 phr. It was found that the usage of 7 phr PVC led to improve interaction between NR and CSM phases. Therefore, increase in cure characteristics, mechanical strength and automotive fuel resistance of the blend was observed.
