Interfacial design of the nonpolar polyolefin ternary composite with high strength, high toughness, and high modulus

Abstract

SYNPOSISAn interfacial model was proposed for the ternary thermoplastics (matrix)/elastomer/rigidparticle filler composite with high strength, high toughness, and high modulus. A dispersed phase of rigid particle as a core and elastomer as a shell that has a good interfacial adhesion with the matrix is the key point of the model. A composite with high strength, high toughness, and high modulus was obtained in the styrene (ST) and maleic anhydride (MAH) modified high-density polyethylene (HDPE)/ethylene-propylene-diene monomer (EPDM) rubber/ carbon black (CB) with ditertiary butyl peroxide (DTBP) as the initiator through the reactive extrusion. The electrical resistivity measurement showed that CB of the unmodified composites distributed at the interface of the HDPE and EPDM, while that of the modified composites distributed mainly in the EPDM phase. The morphology of the ternary composite was consistent with the wetting coefficient analysis. That the mechanical properties of the y-ray-irradiated unmodified composites were not as good as those of the modified composites further indicated that the mechanical properties of the composite could not be improved significantly purely by introducing the interfacial adhesion and matrix crosslinking without forming the proposed dispersed phase structure. SEM observation supported the conclusion that the different phase structures are the major reason that leads to the different toughness. INTRODUCTIONRecently, rigid-particle fillers have been extensively used in creating a polymer composite with high strength, high modulus, and low shrinkage.',' However, the decreased toughness generally results for the c o m p o~i t e .~ On the other hand, elastomers are generally employed in increasing the polymer toughness, but generally result in the deteriorated In a word, two-phase composites exhibit only a partial improvement over the matrix material alone, because some selected properties are enhanced a t the expense of others.* To whom correspondence should be addressed.Journal of Applied Polymer Science, Vol. 59, 287-294 (1996) 0 1996 John Wiley & Sons, Inc.CCC 0021-8995/96/020287-08 In our earlier work, a kaolin-toughened polypropylene l1 and polyamide 6 l2 composite was obtained. In the case of kaolin-toughened polypropylene, an elastic interlayer that had a good interfacial adhesion with the kaolin was inserted between the filler and matrix; therefore, the toughness of the composite was increased significantly. But due to the lack of interfacial adhesion between the interlayer and the matrix, the strength of the composite was not improved. In the case of the kaolin-toughened polyamide 6, the interfacial adhesion both between the filler and interlayer and between the interlayer and matrix was good due to the presence of functional group in both the filler and the matrix. A polyamide 6 composite with high strength, high toughness, and high modulus was obtained. The functionalization of the matrix was not present in the nonpolar polypropylene. As a result, the above interfac...

Mechanical properties and volume dilatation of HDPE/CaCO3 blends with and without impact modifier

“…The development of strong microcomposites requires to disperse homogeneously the particles in the material and to improve their bonding with the polymer matrix. One method to fulfill the latter condition is to introduce a rubbery phase into the composite with a morphology that is a rubber interphase forming core-shell structure [6]. Previous studies have shown that ethylene-octene copolymers (POE) have high tear resistance, which makes them good candidates as packaging materials [7,8].…”

Maleic anhydride grafted thermoplastic elastomer as an interfacial modifier for polypropylene/polyamide 6 blends

“…To reach this goal, the design of the elastomer interlayer is crucial. Our work on high‐density polyethylene (HDPE)/ethylene–propylene–diene monomer (EPDM)/carbon black (CB) composites has shown that bad interfacial adhesion results in separated CB and EDPM phases in the HDPE matrix 16. When an interfacial modifier is used, CB is capsulated in EDPM, and this forms a core–shell structure.…”