Study on polypropylene/natural rubber blend with polystyrene‐modified natural rubber as compatibilizer

Abstract

Polystyrene‐modified natural rubber (SNR) was prepared in the laboratory and subsequently used as compatibilizer in polypropylene/natural rubber (PP/NR) blends. The effect of SNR (at 5%, 10%, 15% and 20% by volume) in PP/NR (70/30) blend was studied by maintaining the rubber volume while PP volume was replaced by SNR accordingly. The sequence of mixing was found to affect the blend morphology and tensile properties. The effect of curatives on the tensile properties of the blends was also investigated. The addition of curatives into the rubbers in PP/NR/SNR improved the tensile properties significantly compared with the PP/NR reference blend. For a semi‐efficient curative system, SNR loading at 10% gave the best overall tensile properties, while for an efficient curative system, 5% SNR loading resulted in improvements in tensile strength and stiffness of over 20% and 40%, respectively, compared with the reference. © 2002 Society of Chemical Industry

Microhardness Studies of the Interphase Boundary in Rubber‐Softened Glassy Polymer Blends Prepared with/without Compatibilizer

“…[1] For instance, poly(methyl methacrylate) (PMMA) is a hard glassy polymer; although highly excellent in optical transparency it is not suitable for some specific end-uses due to its brittle fracture. [6,7] This third component is expected to be distributed around the phase boundary to enhance the adhesion between the blend components, as the coupling agent in case of glass fiber reinforced composites does, and in this way significantly improves the mechanical properties of the blend material. [2 -5] However, unlike copolymers where the chemically different monomer units are linked by chemical bonds, blending creates serious problems, especially in the achievement and preservation of the final degree of dispersion if the two polymer partners of the blend are not thermodynamically miscible.…”

Efficiency of high energy electrons to produce polypropylene/natural rubber‐based thermoplastic elastomer

“…However, most of the commercially available polymer blends lag behind due to inherent incompatibility of the blend components [7]. Molecular level compatibility is not achieved for a PP/NR blend [24]. So, many studies have been devoted to increase the compatibility of this system [24–27].…”

“…Molecular level compatibility is not achieved for a PP/NR blend [24]. So, many studies have been devoted to increase the compatibility of this system [24–27]. In common practice, a third component, typically a copolymer, may be added as a compatibilizer or a chemical reaction can be induced to modify the interfacial adhesion in the two‐phase polymer blend [26].…”

Prediction of styrene conversion of polystyrene/natural rubber graft copolymerization using reaction conditions: Central composite design versus artificial neural networks

“…For instance, grafting a small amount of glycidyl methacrylate (GMA) onto NR using emulsion polymerization produces a polymer blend of GMA and NR polymers and GMA/NR graft copolymer that occur during the polymerization, exhibiting improved tensile strength and modulus with insignificant loss in elongation at break, which has led to the use of this polymer blend as seal, adhesive, and coating 2. The improved properties are ascribed to the existence of vinyl polymer possessing better properties and of the graft copolymer in the polymer blend, which helps reduce the interfacial energy between the vinyl polymer and the rubber phases, and thus it can be said that that graft copolymer acts as a compatibilizer 3–6. Better mechanical properties also happen for the styrene/NR blend which are compatibilized by using styrene/NR graft copolymer, of which modulus and hardness are higher than those of neat NR 7…”

“…2 The improved properties are ascribed to the existence of vinyl polymer possessing better properties and of the graft copolymer in the polymer blend, which helps reduce the interfacial energy between the vinyl polymer and the rubber phases, and thus it can be said that that graft copolymer acts as a compatibilizer. [3][4][5][6] Better mechanical properties also happen for the styrene/NR blend which are compatibilized by using styrene/NR graft copolymer, of which modulus and hardness are higher than those of neat NR. 7 To graft styrene and NR using free-radical emulsion polymerization, redox initiator is the most suitable to initiate the graft copolymerization because it not only works well at high pH (the presence of ammonia in NR latex) but also is insensitive to the existence of oxygen in the system.…”