摘要:

In this study, bottles of mineral water and yogurt as well as Styrofoam bowls were recycled and identified by infrared spectroscopy as poly(vinyl chloride) (PVC), high-impact polystyrene (HIPS), and polystyrene (PS). Solution blending was employed to make polymer blends from these recycled plastics, including PVC/PS, PVC/HIPS/PS blends, and PVC/HIPS blends with or without a com-patibilizer, styrenelp-chlorostyrene (ST-CMS). Thermal behavior from differential scanning calorimetry was used to examine the compatibility of the blends. For the PVC/PS and PVC/HIPS/PS systems, it is found that although the third component (HIPS) may not be good enough as a compatibilizer, the addition of HIPS to the two-component blend (PVC/PS) may enhance the mechanical properties at the specific composition, especially for the blends at the intermediate concentrations. For PVC/HIPS blends with the ST-CMS copolymer as a compatibilizer, all the mechanical properties of the blends except the elongation at break, in general, increased with increasing the concentration of compatibilizer due to the increase of compatibility. The abnormal fracture strain was attributed to the differences in adhesion when various amounts of ST-CMS was added. The results of mechanical properties of the blends were consistent with the morphology from scanning electron microscopy.

ISSN:0360-2559    

DOI:10.1080/03602559909351629

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The polymer composites of HDPE and banana, hemp, and agave fibers (50 : 50, w/w) were prepared separately with and without treatment of maleic anhydride. The swelling phenomenon in terms of absorption of water and steam was studied and it was found that the steam penetrates more within a smaller period of time than the water at ambient temperature. The maleic anhydride treatment on these fibers showed the ester-ification of fibers, and because of that, the absorption (swelling) of steam and water is less than the untreated respective fibers composites.

ISSN:0360-2559    

DOI:10.1080/03602559909351630

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

White rice husk ash (WRHA)-filled natural rubber compounds were prepared by using a laboratory-size two-roll mixing mill. Curing using a conventional vulcanization system was used and cure studies were carried out on a Monsanto rheometer. The mechanical testing of the vul-canizates involves the determination of tensile properties, tear strength, hardness, and resilience. Scanning electron microscopy (SEM) and swelling measurement were also done. The effects of bonding agents on the curing and mechanical properties have been investigated using re-sorsinol formaldehyde and hexamethylene tetramine as the bonding agents. Results show that the bonding agents prolonged the cure timet90and scorch timet2and, at the same time, improved the mechanical properties of the natural rubber vulcanizates. SEM and swelling studies indicate that the rubber-filler interaction is improved with the addition of bonding agents.

ISSN:0360-2559    

DOI:10.1080/03602559909351631

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The variation of the ultimate stress and the elastic modulus of four different natural fiber-resin matrix composites was evaluated as a function of the aging of these composites in distilled water. Their diffusion coefficients and the maximum water content were also determined by fitting the experimental data to the Fickian model for diffusion. The composites analyzed were the common jute- and sisal-polyester matrix as well as jute- and sisal-epoxy resin matrix. The overall mechanical behavior observed could be qualitatively explained by the topographic aspects generated at the fracture surfaces. The jute-epoxy composite showed the best properties over all the immersion times analyzed. A strong fiber-matrix interface was developed for this composite and is partially responsible for its better behavior. The experimental data also show that the sisal fibers are more affected by water than jute fibers.

ISSN:0360-2559    

DOI:10.1080/03602559909351632

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Metal chelates of three grades of carboxymethyl cellulose (CMC) (LI-L3) with Cu(II) ions, either originating from CuCl2or CuSO4, were prepared and characterized by elemental analysis, infrared spectra, and electrical conductivity studies. The results showed that the degree of substitution of CMCs and the origin of the Cu(II) ion have a profound effect on the amount of metal included in the polymer complexes and the structure and the electrical conductivity of the prepared complexes. CMC acts as a uninegatively charged bidentate ligand when it is chelated with Cu(II) of CuCl2via the carboxymethyl group and exhibits the formula Cu(L)2, whereas it acts as a binegatively charged bitentate ligand when it is chelated with CuSO4via the carboxymethyl and secondary hydroxyl groups and exhibits the formula CuL.2H2O. The investigation revealed that the electrical conductivity depends on the temperature and has two maximum peaks. The values of the activation energy for the conductivity of CMC and their complexes indicated that the samples changed from a low-semiconductor to a high-semiconductor property with heating. It is found that CMC-Cu(II) complexes formed from CuSO4exhibit a high-semiconductor property compared to complexes derived from CuCl2.

ISSN:0360-2559    

DOI:10.1080/03602559909351633

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Certain investigations on the effective bond strength of gum adhesive extracted from kendu (Diospyros cordifolia Roxb) fruit have been studied with respect to different interfaces such as general-purpose wood-wood, teakwood-teakwood, plywood-plywood, glass-glass, PMMA-wood, PVC-PVC. LDPE-LDPE, HDPE-HDPE, and PMMA-PMMA. The effects of different parameters such as curing temperature, curing time, thickness of specimens, and presolvent treatments on the bond strength of kendu fruit adhesive (KFA) are investigated. The bond strengths of KFA under different hazardous environments such as boiling water, saline water, and kerosene oil, acidic as well as alkaline solutions for the teakwood-teakwood interface have also been examined. A comparative account of studies of the effective bond strength of KFA with three different commercial synthetic adhesives such as Varnicol, Quickfx, and Araldite is reported. The KFA shows a superior bond strength for general-purpose wood-wood adhesion. Its bond strength is also comparable with synthetic adhesives for certain plastic-plastic as well as teakwood-teakwood adhesions. The retention of effective bond strength of KFA in various hazardous atmosphere remarkably encourages an industrial-grade adhesive formulation through proper R&D investigations. Adequate modifications and informations are required for an improved adhesive formulation from this natural adhesive to meet the industrial standard.

ISSN:0360-2559    

DOI:10.1080/03602559909351634

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The aim of this article is the modeling and simulation of the batch bulk polymerization of methyl methacrylate (MMA). Simple dependencies between the propagation and termination rate constants and monomer conversion for the gel and glass effects are proposed. The empirical parameters in these relations are determined from conversion and molecular-weight experimental data obtained under various reaction conditions (initiator concentration and temperature). Sometimes, different relations were necessary to express the variation of the kinetic constants on conversion subintervals. Thus, these models have been used continuously or discontinuously, as a function of their results. An algorithm for using this model was also established.

ISSN:0360-2559    

DOI:10.1080/03602559909351635

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

ISSN:0360-2559    

DOI:10.1080/03602559909351636

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

ISSN:0360-2559    

DOI:10.1080/03602559909351618

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor