Abstract:To expand the range of properties and the range of types of thermoplastic elastomer (TPE), materials based on ternary blends of polypropylene and polar and non-polar rubbers were produced and investigated. To obtain blended and dynamically vulcanised materials, one- and two-stage methods were tested. It was established that the best properties are possessed by composites produced using master batches (rubber mixes) based on a thermoplastic vulcanisate (TPV) rubber phase, and to improve the combination of polym… Show more
“…%), the crosslink density and mechanical stress concertation of the rubber phase increased sharply, thereby lowering the rubber particle size and improving its dispersion within the PP matrix. 27 The excess of SSA-LDH particles showed a tendency to locate at PP/PUR interface, increasing the compatibility and interfacial adhesion between nonpolar matrix and relatively polar rubber phase. The variation trend of the effect of rubber particle size is shown in Supplementary Figure S3.Figure 6.Scanning electron micrographs determined for the etched PP/PUR TPV samples: (a) TPV0; (b) TPV3; (c) TPV5.…”
Herein, a novel polypropylene/polyurethane rubber (PP/PUR) was prepared based on thermoplastics vulcanizates (TPV)/layered double hydroxide (LDH) nanocomposite in the presence of 3-(triethoxysilyl)propylsuccinic anhydride (SSA) intercalated LDH (SSA-LDH). The effect of SSA-LDH was explored on thermo-mechanical, thermal, morphological, rheological, and mechanical properties as well as gel content, compression set, X-ray photoelectron spectroscopy analysis, and cross-linking density (CLD) of TPV based on PP/PUR with the weight ratio of 40/60. It was found that the crystallization, tensile strength, gel content, cross-linking density, young’s modulus, elongation at break, melting point, and damping factor significantly changed with increasing SSA-LDH content in PUR/PP TPVs. The reasons could be attributed to cross-linking induced by SSA-LDH and curing agent Bis-(triethoxysilylpropyl) tetrasulfide (also called (Si-69)) that grafted onto PUR chains, resulting in good dispersion of fine PUR vulcanized particles into PP matrix. This claim was confirmed by studying the rheological properties through Rheometeric mechanical spectroscopy and dynamic-mechanical analysis. Field emission scanning electron microscope images confirmed the improved compatibility between PUR and PP by adding SSA-LDH. The gel content and CLD of TPV samples without SSA-LDH were 20% and 2.75 mol/mL, respectively, which showed a significant increment to 25.5% and 4.5 mol/L upon adding 5 wt. % SSA-LDH. The highest elongation at break, tensile strength, and young’s modulus were 525%, 16.5 MPa, and 210 MPa, respectively which were observed for TPV5.
“…%), the crosslink density and mechanical stress concertation of the rubber phase increased sharply, thereby lowering the rubber particle size and improving its dispersion within the PP matrix. 27 The excess of SSA-LDH particles showed a tendency to locate at PP/PUR interface, increasing the compatibility and interfacial adhesion between nonpolar matrix and relatively polar rubber phase. The variation trend of the effect of rubber particle size is shown in Supplementary Figure S3.Figure 6.Scanning electron micrographs determined for the etched PP/PUR TPV samples: (a) TPV0; (b) TPV3; (c) TPV5.…”
Herein, a novel polypropylene/polyurethane rubber (PP/PUR) was prepared based on thermoplastics vulcanizates (TPV)/layered double hydroxide (LDH) nanocomposite in the presence of 3-(triethoxysilyl)propylsuccinic anhydride (SSA) intercalated LDH (SSA-LDH). The effect of SSA-LDH was explored on thermo-mechanical, thermal, morphological, rheological, and mechanical properties as well as gel content, compression set, X-ray photoelectron spectroscopy analysis, and cross-linking density (CLD) of TPV based on PP/PUR with the weight ratio of 40/60. It was found that the crystallization, tensile strength, gel content, cross-linking density, young’s modulus, elongation at break, melting point, and damping factor significantly changed with increasing SSA-LDH content in PUR/PP TPVs. The reasons could be attributed to cross-linking induced by SSA-LDH and curing agent Bis-(triethoxysilylpropyl) tetrasulfide (also called (Si-69)) that grafted onto PUR chains, resulting in good dispersion of fine PUR vulcanized particles into PP matrix. This claim was confirmed by studying the rheological properties through Rheometeric mechanical spectroscopy and dynamic-mechanical analysis. Field emission scanning electron microscope images confirmed the improved compatibility between PUR and PP by adding SSA-LDH. The gel content and CLD of TPV samples without SSA-LDH were 20% and 2.75 mol/mL, respectively, which showed a significant increment to 25.5% and 4.5 mol/L upon adding 5 wt. % SSA-LDH. The highest elongation at break, tensile strength, and young’s modulus were 525%, 16.5 MPa, and 210 MPa, respectively which were observed for TPV5.
“…We have developed TPVs based on polypropylene (PP) and a combination of isoprene rubber (SKI) and nitrile butadiene rubber (BNKS-28 AMN) with a ratio of the polymer components PP/SKI/BNKS of 30/60/10 (referred to below as TPV 30/60/10) in the presence of a sulphur accelerating vulcanising system [2, 3]. The pronounced boundaries of dispersed phase that were found in previous investigations [4], the existence of a concentration gradient through the volume, and the presence of pores irrespective of the method of TPV preparation indicate the need to modify both the polypropylene macromolecules and the non-polar and polar rubbers in the composition of the elastomer phase, i.e. the need to increase the interaction between the polymer components.…”
The possibilities of increasing the interaction between the components of previously developed thermoplastic vulcanisates based on polypropylene and a combination of isoprene and nitrile butadiene rubbers were studied. The morphology of the composites was recorded by means of optical microscopy using an analytical complex based on a Leica DM-2500 optical microscope, a Leica DFC-420C digital high-resolution colour camera with a Peltier cooling system, and a specialised computer desk. The parameters of crystallisation of polypropylene were measured by differential scanning calorimetry using a DSC 204F1 Phoenix instrument (Netzsch). The physicomechanical properties of the vulcanisates were also determined. Maleinised polypropylene, a copolymer of ethylene with vinyl acetate, and their mixtures were used as compatibilising additives. Maleinised polypropylene was introduced together with polypropylene in a quantity of 1–10 parts; no changes in properties were observed with increase in the dosage above 4 parts, so this dosage was used. The copolymer of ethylene with vinyl acetate (1–10 parts) was introduced into the rubber phase at the stage of rubber mix preparation specially to improve the compatibility of polypropylene and nitrile butadiene rubber. The introduction of maleinised polypropylene leads to an increase in the workability and in the level of elastic strength properties, in particular the tensile elastic modulus and hardness. A considerable increase in the uniformity of distribution of components throughout the volume, a finer dispersion of the rubbers in the polypropylene matrix, and a reduction in the number of pores in the material were shown, and also an increase in the degree of polypropylene crystallinity measured under experimental conditions. The most positive effect is observed with the combined introduction of the copolymer of ethylene with vinyl acetate and the maleinised polypropylene: the nominal stress under elongation increases by 34%, and the elongation at break by 15%. The combined introduction of the compatibilising additives improves the compatibility of the components of the system, the phase boundaries become more diffuse, there is a reduction in the optical density of rubber-rich zones, and these zones are penetrated by polypropylene fibrils.
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