SYNOPSISFour different types of high-density polyethylenes (HDPE) were blended with perlite at different concentrations. Silane coupling agent y-aminopropyltriethoxy silane ( y-APS, A-1100) was used to enhance the adhesion between perlite and HDPEs. Ultimate tensile strength and elastic modulus increased as the perlite content increased, while ultimate elongations decreased with the increasing amount of perlite. Exceptional variations in the measured properties are explained in terms of the differences in polyethylenes used in the composites. The biggest improvement in ultimate tensile strength was observed in the highly crystalline polyethylene; on the other hand, in the absence of silane coupling agent the high molecular weight polyethylene showed the least improvement in tensile strength. The effect of branching in HDPE composites was demonstrated. The enhancement of interfacial adhesion by using a coupling agent was also examined by scanning electron microscopy (SEM) . 0 INTRODUCTIONThe mechanical and other characteristic properties of composites are vital for designing materials, and the prediction of these properties from the filler and matrix properties has considerable importance. Filler characteristics such as type of filler, 1-5 size and size distribution, 6,7 shape, 1,4,5*8 and concentration'-" have been shown to affect the mechanical and other properties of the composites. Polymer characteristics influencing the mechanical properties of the composites can be summarized as molecular weight, l 2 degree of branching or crosslinking,2 and crystallinity and m~rphology.'~.~~ Regarding the variation and enhancement of the mechanical properties in a composite material, the key point is the interfacial adhesion between the matrix and the filler. The most crucial factor which directly influences the mechanical properties is the strength and the weakness of the load transfer between the polymer and the filler and, therefore, the * To whom correspondence should be addressed. CCC 0021-8995/94/081103-12 interfacial adhesion. By using certain coupling agents which promote the adhesion between two different materials, the interaction can be improved and optimum mechanical properties can be achieved. l 4 9 l 5In some cases, the mechanical properties of the composites can be predicted from basic principles. However, sufficient knowledge about polymer-filler interaction does not exist; hence, to determine the property changes, experimental methods are generally used. These properties are generally modulus, ultimate properties, yield stress, impact strength, and flexural properties.Modulus, which is a bulk property, depends primarily on the geometry, 4,5 particle size, 6,7 and concentration 1-7,9-12 of the filler and can be described by several equations.'6-20 In general, modulus (stiffness) increases with the addition of filler because flexing of the matrix is prevented by the relatively high modulus filler particles.By definition, the ultimate tensile strength of composites is described as the maximum achievable stre...
This study covers the preparation and characterization of perlite-filled polypropylene (PP). The compositions of 15, 30, and 50 % by weight perlite-PP composites were prepared by melt-mixing. The PP used in this study was either applied in the virgin form or ␥-irradiated in air at the doses of 10, 25, 50, and 100 kGy to determine the effect of oxidative degradation in composite properties. Furthermore, the active sites containing oxygen produced by ␥-irradiation in PP may provide a possible enhancement by the interfacial interaction between perlite and PP. An initial sharp drop in torque readings during the melt-mixing of perlite-PP composite preparation indicated an extensive chain scission and degradation by ␥-irradiation. The thermal properties of the composites were characterized by DSC. The ultimate tensile strength and elongation and also impact strength decreased in all composites with ␥-irradiation. Yet, these changes appeared not to be faster than was the change in unfilled PP upon irradiation. Scanning electron microscopy revealed an interfacial adhesion between perlite and irradiated PP while virgin PP did not show any evidence of adhesion.
SYNOPSISThermal and flow properties of perlite-filled high-density polyethylenes ( HDPE) , studied in the first part of the paper, are discussed. Maximum peak temperatures of endotherms ( TmP) and the corresponding relative peak heights were examined by differential scanning calorimetry (DSC). The data obtained from a Brabender torque rheometer were evaluated to find the melt viscosities at low shear rate during preparation of perlite-HDPE composites. The filler concentration, types of HDPEs, and the use of 7-APS are found to be effective and influential factors on the thermal and flow properties of these composites. 0 1994 John Wiley & Sons, Inc.
SYNOPSISImpact properties of perlite-filled high-density polyethylene (HDPE) composites were studied with the Charpy method by using both notched and unnotched samples. y-Aminopropyltriethoxy silane (y-APS, A-1100) was used as a silane coupling agent to improve the interfacial adhesion. The influences of the molecular parameters of HDPEs, molecular weight, degree of branching, degree of crystallinity, and also the effect of y-APS on the impact properties are represented in this work. 0 1995 John Wiley & Sons, Inc.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.