Papers by Keyword: Polymer Blend

Abstract: Porous carbon monoliths are prepared by carbonization of a simple polymer blend, in which phenolic resin (PF) as carbon precursor, polyvinyl butyral as pore former and activated carbon as conducting additive and contraction inhibitor are used to make polymer blend. The results show that the carbon monoliths, with a narrow pore size distribution with mean controlled diameters in the sub-micron/micron range, can be easily produced by controlling the stabilization temperature of the PF, the carbonization temperature, and particle diameters of the precursor powders. The pore size decrease as the stabilization temperature of the PF increases or the particle diameters of the precursor powders decreases. The electrical resistance of the carbon monoliths decreases as the carbonization temperature increases, but the average pore diameter and volume of the carbon monoliths are almost constant as the carbonization temperature increases.

Abstract: To evaluate the effect of the size of the microstructure on the mechanical property of the cavitated rubber blended (voided) amorphous polymer, the FEM simulation based on the rate form second-order homogenization method, in which rates of the macroscopic strain and strain gradient are given to the microstructure, was performed. Computational simulations of micro-to macroscopic deformation behaviors of amorphous polymers including different sizes and volume fractions of the voids were performed. Non-affine molecular chain network theory was employed to represent the inelastic deformation behavior of the amorphous polymer matrix. With the increase in the volume fraction of the void, decrease and periodical fluctuation of stress and localized deformation in the macroscopic field were observed, and were more emphasized with the increase in the size of the void. These results were closely related to the non-uniform deformation and volume increase of the void in the microscopic field.

Abstract: A new method is proposed to improve blend compatability through inclusion complexation. The host polymer and the guest polymer are synthesized respectively and blended to form a film. The transparency of blend film increases and, at some composition, a third T_g is obsereved, indicating the inclusion complex between these two polymers

Abstract: Studies on the effect of percentages of epoxide group in thermoplastic elastomer as a compatibilizer on properties of polyamide6 (PA6) and low-density polyethylene (LDPE) blends was successfully carried out in this study. Thermoplastic epoxidized natural rubber (TPENR), made from epoxidized natural rubber (ENR) and LDPE, prepared from 3 types of ENR, i.e., ENR-20, ENR-50 and ENR-70, with the ratio of 90/10 of LDPE/ENR by weight. TPENR was applied as a compatibilizer into the blend of PA6/LDPE/TPENR at the ratio by weight of 80/20/1 by using a twin screw extruder at 235°C. All test specimens were characterized for phase morphology, impact strength and rheological behaviour. Results exhibited that phase morphology of PA6/LDPE blend was incompatible. The addition of TPENR improved the compatibility of PA6/LDPE blends. With inclusion of TPENR-20 as a compatibilizer, the uniformity and the maximum reduction of dispersed phase sized were observed. Moreover, it was revealed that the rheological properties such as shear viscosity increased when compared with PA6/LDPE incompatible blend. In addition, it was found that the highest shear viscosity and also the highest impact strength were obtained for the blend of PA6/LDPE compatibilized by TPENR-20. This result was further supported by SEM images, which showed that the smallest dispersed phase size occurred when a TPENR-20 was used as a compatibilizer. So, it was clearly demonstrated in this study that the suitable type of TPENR, i.e., TPENR-20, has an effect on improving phase morphology and properties of PA6/LDPE blends.

Abstract: In the current study, poly (hydroxy butyrate-co-hydroxy-valerate) (PHBV) was blended with a synthetic polymer poly (L-lactic acid) (PLLA), to control the degradation rate and process of composite scaffolds, as PLLA has a much higher degradation rate than PHBV. PHBV/PLLA blends were used as polymer matrices for composite scaffolds. Emulsion freezing / freeze-drying technique was used to fabricate composite scaffolds based on these blends and containing nanosized hydroxyapatite (nHA). In vitro degradation tests of composite scaffolds were conducted by immersing samples in phosphate buffered saline (PBS) for various periods of time. It was found that the composition of polymer blends affected water uptake of scaffolds. Composite scaffolds exhibited enhanced adsorption of bovine serum albumin (BSA), a model protein.

Abstract: Phase composition of gelatin-starch blends were investigated by Fourier transform infared (FTIR) spectroscopy with various extended techniques, from ATR to 2D and 3D mapping by synchrotron FTIR micro-spectroscopy. The peaks of the saccharide bands (1180953 cm^-1) and the amide I and II bands (17501483 cm^-1) were used to identify the starch and gelatin respectively. The ratio of the areas of the saccharide bands the amide I and II bands was used to determine relative distributions of the two components of the blends.

Abstract: Polymer blends are better technological response to generate "new" high performance polymers from commercially available polymers and are an alternative to obtaining polymer materials with properties that generally are not found in a single material. The thermoplastic modified with elastomer and/or thermoplastic elastomers have attracted great interest from researchers and industries due to the attractive cost/benefit ratio and the possibility of a significant increase in the toughness of brittle polymers or temperatures subenvironment with the incorporation of a dispersed rubber phase. The destination of compound by recycled rubber has been one of the main problems faced by humanity, because its natural degradation occurs after a long time due to the presence of cross-links, stabilizers and other additives in their structure, causing damage to the environment. This study aimed to prepare blends of polyamide 6/PE-g-MA /compound by recycled rubber (SBRr).

Abstract: In this work, the effect of the PCL content and E-GMA compatibilizer on the mechanical properties and morphology of poly (lactic acid) - PLA/ poly (ε-caprolactone)-PCL blends was investigated. The results of the mechanical properties showed that there was a reduction in the elastic modulus and tensile strength when PCL was added to PLA. The decrease in the modulus was more pronounced when the PCL content was increased from 10 to 20% (wt). The PLA/PCL/E-GMA blend showed the lower modulus and tensile strength. This blend also presented the higher elongation at break and impact strength. The morphology analysis by SEM showed that the PLA/PCL blends where characterized by lack of adhesion between the PLA and PCL phases. The presence of E-GMA in the PLA/PCL/E-GMA blend improved the adhesion between the PLA and PCL phases.Keywords: poly (latic acid); poly (ε-caprolactone); polymer blends; compatibilizer

Abstract: The effect of the silane treated talc on the mechanical and thermal properties of talc filled thermoplastic polyurethane/polypropylene blends (TPU/PP blends) was investigated. Thermoplastic polyurethane and polypropylene are partially miscible due to the lack of interfacial interaction between the nonpolar crystalline PP and polar TPU. Blends of TPU and PP with silane treated and untreated-talc were prepared using melt blending in a laboratory twin-screw extruder. Organosilane (3-glycidoxypropyl-trimetoxy silane coupling agent) was used to treat talc in order to improve the affinity between the filler and the TPU/PP blends. Dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC) and mechanical (tensile test) measurements were used to characterize the talc filled and silane treated talc filled composites and TPU/PP/talc blends. The addition of silane treated and untreated talc in TPU/PP blends improved miscibility in all investigated TPU/PP/talc blends. The silane treatment increases the storage modulus in all investigated TPU/PP/talc blends in comparison with that of the untreated TPU/PP/talc blends. The obtained DSC results show that the addition of silane treated talc increases the degree of crystallinity (χc) of TPU/PP/talc blends because of the improved adhesion between the polymer and the treated talc. Addition of silane treated talc improved the mechanical properties as compared to TPU/PP/talc blends without chemical modification of talc. The results of strength correlate to the values of the storage modulus and crystallinity of the investigated TPU/PP/talc blends.

Abstract: The mixing efficiency of intermeshing rotor internal batch mixers for the preparation of rubber-rich thermoplastic vulcanizates (TPV) based on ethylene propylene diene terpolymer (EPDM) and polypropylene (PP) blends was investigated. Two laboratory scale mixers, namely intensive batch mixer (INS) and kneader batch mixer (KND), were used. The mixer choice at controlled mixing conditions was investigated to determine its effects on morphological and mechanical properties and crosslink density of the prepared EPDM/PP TPVs. Such effects were found on the degradation of the polymer, on the distribution of the EPDM phase in the blend morphology, particularly the size of EPDM inclusion, and on the crosslink density of the EPDM phase. In summary, the different mixing efficiencies of INS and KND type mixers affect the EPDM/PP TPVs and their properties. Also, the INS mixer has higher mixing efficiency than the KND mixer.