Mechanical Properties of Talc Filled i-PP/CSM Rubber Composites

ABSTRACT

Tensile and impact properties of talc-filled i-PP/CSM rubber (20 phr, 0.13 vol fraction) blends were studied in the talc concentration range 0–0.149 vol fraction (0–50 phr). The tensile modulus increased whereas the tensile breaking strength and the strain-at-break decreased with increase in the talc concentration. The modulus increase and the strain decrease were due to enhanced mechanical restraint imposed by the talc particles on the polymer blend decreasing its deformability. Formation of stress concentration points explained the decrease in the tensile strength. The Izod impact strength showed a significant decrease with increase in the filler content. Surface treatment of the talc particles with a titanate coupling agent LICA 12 increased the wetting of the talc by the polymer blend, further modifying the strength properties. Scanning electron microscopic studies showed enhanced dispersion of the filler particles sequential to the surface treatment, effecting modifications of the composite strength properties.     

Curing Characteristics and Mechanical Properties of Oil Palm Wood Flour Reinforced Epoxidized Natural Rubber Composites

Abstract

The paper reports on the curing characteristics and mechanical properties of oil palm wood flour (OPWF) reinforced epoxidized natural rubber (ENR) composites. Three sizes of OPWF at different filler loadings were compounded with a two roll mill. The cure (t ₉₀) and scorch times of all filler size decrease with increasing OPWF loading. Increasing OPWF loading in ENR compound resulted in reduction of tensile strength and elongation at break but increased tensile modulus, tear strength and hardness. The composites filled with smaller OPWF size showed higher tensile strength, tensile modulus and tear strength. Scanning electron microscope (SEM) micrographs showed that at lower filler loading the fracture of composites occurred mainly due to the breakage of fibre with minimum pull-out of fibres from the matrix. However as the filler loading is increased, the fibre pull-out became very prominent due to the lack of adhesion between fibre and rubber matrix.     

氧化铅硫化体系的配合对氯磺化聚乙烯橡胶性能的影响

采用对比试验法和正交试验法,研究了氧化铅硫化体系中配合剂的种类和用量对氯磺化聚乙烯橡胶性能的影响。结果表明,在CSM氧化铅硫化体系配合中,氧化铅和促进剂TRA是影响性能的主要因素;促进剂TRA并用促进剂DM后,可提高CSM硫化胶的拉伸强度、定伸应力;促进剂TRA与TT相比,CSM硫化胶拉伸强度和定伸应力大,永久变形小;氢化松香作为活性剂与松香、SA相比,CSM硫化胶拉断伸长率和撕裂强度高,拉伸强度和定伸应力较大;采用PbO/MgO并用硫化剂,CSM硫化胶硬度、拉伸强度和定伸应力提高,拉断伸长率和撕裂强度下降。     

Studies on Polycarbonate and Polydimethylsiloxane Rubber Blends

Polycarbonate (PC) and polydimethylsiloxane (PDMS) rubber blend were made by melt blending using a twin-screw extruder. The blends were characterized by mechanical testing, thermal studies, electrical properties and morphological studies. The notched lzod impact strength increased greatly when the rubber content was 20%. The morphology of PC/PDMS blends showed dispersed rubber particle in the PC matrix. The impact strength, which increased with PDMS rubber concentration, has been analyzed on the basis of the interphase adhesion and crazing mechanisms. Tensile and flexural modulus as well as strength decreased with increase in PDMS rubber content. Predictive models have been used to explain the tensile modulus and strength properties. Incorporation of PDMS decreases the glass transition temperature of PC and facilitates its processing. Scanning electron microscopy has been employed to study the phase structure.     

氯磺化聚乙烯对三元乙丙橡胶耐热老化性能的影响

研究氯磺化聚乙烯(CSM)和氯化聚乙烯(CM)对三元乙丙橡胶(EPDM)物理性能及耐热老化性能的影响。结果表明:CSM具有独特的氯磺酰基,添加CSM的EPDM胶料定伸应力与拉伸强度增大,耐热老化性能明显提高;添加CM的EPDM胶料耐热老化性能无明显改善;添加气固法CSM3570与溶剂法CSMTS530的EPDM胶料耐热老化性能相近;气固法CSM3570用量为5份时,EPDM胶料耐热老化性能较好,性价比较高。     

Effects of PBO fiber and clay on the mechanical,morphological, and dynamic mechanical properties of NR/HDPE blends

Poly(p‐phenylene‐2,6‐benzobisoksazole) (PBO) and natural rubber (NR)/high density polyethylene (HDPE) composites were melt‐blended in a Haake internal mixer. The tensile strength, tensile modulus, and impact strength increased with fiber loading and optimized at 20%. Incorporation of clay into the NR/HDPE/PBO composites resulted in an improvement of tensile strength for NR/HDPE/PBO composites compared to the systems without clay. However, addition of clay was only effective at low contents (5–7.5%). Additional improvement of tensile strength, tensile modulus, and impact strength of the hybrid composite was observed on addition of liquid natural rubber (LNR). Scanning electron micrographs of the samples had indicated that the presence of clay decreased the domain size of the dispersed phase. Results on dynamic response showed that incorporation of clay and LNR into the composites had increased the storage modulus and reduced the tan δ. The shift of glass transition temperature (T_g) to higher values for composites also indicated good interaction between the fiber and the matrix. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers.     

White Rice Husk Ash Filled Natural Rubber/Linear Low Density Polyethylene Blends

Abstract

Natural rubber (NR)/Linear low density polyethylene (LLDPE) blends were prepared using an internal mixer at 150°C and a rotor speed of 55 rpm. The tensile strength, tensile modulus and hardness increase with increasing LLDPE content whereas elongation at break and mass swell show decreasing trend. With 30/70 (W/W) NR/LLDPE blends, the increasing white rice husk ash (WRHA) loading also increases the tensile modulus and hardness but reduced the tensile strength, elongation at break, and mass swell.     

Wood flour as a secondary filler in carbon black filled of styrene butadiene/chlorosulphonated polyethylene rubber blend

A study is reported which aims to identify the optimum contents of wood flour (WF) to be introduced into styrene butadiene/chlorosulphonated polyethylene (SBR/CSM) rubber blend compounded with carbon black. A range of composite properties are considered including cure characteristics and mechanical properties, as well as the adhesion strength (rubber‐to‐metal bonding) behavior. Processing characteristic such as maximum torque increases with increasing of the concentration of WF up to 40 phr in SBR/CSM blend, whereas the scorch time and optimum cure time decreases. Results indicated that the tensile strength and tensile modulus, as well as shore hardness of the SBR/CSM composite in which SBR is predominant, increase in a compliance with the increase of WF. Adhesion strength value on peel between metal and WF filled SBR/CSM rubber blend increases when the filling level increases and the maximum value were observed at 40 phr of WF. The enhancement in mechanical properties was supported by data of crosslink density in these samples obtained from swelling measurement. Addition of WF was recommended as an economical and ecological benefit to industries as the properties of the rubber/carbon black composites remained unchanged with increasing WF content. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers.     

Fabrication of Super Tough Polycarbonate/Styrene-Etylene-Butylene-Styrene Grafted Maleic Anhydride (SEBS-g-MA) Blends: Morphological,Short Term Static Mechanical and Fracture Performance Interpretation

Impact behaviours, tensile properties and fracture performance of polycarbonate (PC)/styrene ethylene-butylene-styrene-grafted-maleic anhydride (SEBS-g-MA) copolymer blends at SEBS-g-MA volume fraction Φ_d = 0–0.39 are evaluated. In presence of rubber a significant augmentation in notched Izod impact strength was observed while tensile modulus and strength decreased. Morphological studies reveal good interaction between the PC and the rubber particles showing homogeneous dispersion of SEBS-g-MA in the polycarbonate matrix. Interparticle distance of the dispersed phase evaluated from the morphology studies by scanning electron microscopy (SEM) and the impact strength dependence on the concentration of the blending rubber were analysed. The essential work of fracture approach is applied to study fracture properties of the blends. With increasing SEBS-g-MA concentration nonessential or plastic work increased which explained the enhancement of impact strength of blends.     

Simultaneous full‐interpenetrating polymer networks of blocked polyurethane and vinyl ester. II. Static and dynamic mechanical properties

Simultaneous full‐interpenetrating polymer networks (full‐IPNs) based on blocked polyurethane (PU) and vinyl ester (VE) have been prepared. The static and dynamic properties of these IPNs have been examined. Results show that the tensile strength and flexural strength of IPNs increased with blocked PU content to a maximum value at 7.5 wt % PU content and then decreased. The tensile modulus, flexural modulus, and hardness of IPNs decreased with increasing blocked PU content. The impact strength of IPNs increased with increasing blocked PU content. The tensile strength, flexural strength, tensile modulus, and flexural modulus of IPNs increased with filler (kaolin) content to a maximum value at 20 to 25 phr filler content and then decreased. The higher the filler content, the greater the hardness, and the lower the impact strength of IPNs. The tensile strength, flexural strength, tensile modulus, flexural modulus, and hardness of IPNs increased with increasing VE initiator content. The dynamic technique was used to determined the damping behavior across a temperature range. Results show that the glass transition temperature (T_g) of IPNs are shifted inwardly compared with pure PU and VE, which indicated that the blocked PU–VE IPNs showed excellent compatible. Meanwhile, the glass transition temperature was shifted to a higher temperature with increased filler content. The dynamic storage modulus (E′) of IPNs increased with increasing VE and filler content. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1977–1985, 1999     

Effect of rubber-phase volume fraction in impact polystyrene on mechanical behaviour

The nature and the amount of the rubber-reinforcing phase in impact polystyrene is of critical importance for a good balance of physical properties. It is difficult to change the rubber phase uniquely because of many interdependent variables in the synthesis of impact polystyrene. However, an attempt has been made to prepare rubber-modified polystyrenes with only the rubber-phase volume fraction (RPVF) as a variable. It was found that notched Izod impact strength increased linearly with RPVF, while tensile yield strength was inversely proportional (over the range covered). The area under the rubber damping peak in torsion pendulum measurements was also proportional to impact strength.     

Physico-mechanical and dynamic mechanical studies of nanographite reinforced chlorobutyl nanocomposites

Abstract

Nanographite reinforced chlorobutyl elastomer (CIIR) nanocomposites were prepared. The dispersion of the nanographite in the CIIR matrix has been investigated by scanning electron microscopy. The effect of increasing nanographite loadings (2, 4, 6 and 8 phr) on mechanical properties like tensile strength, hardness, elongation at break and modulus (100, 200 and 300%) has been studied. The study shows increase in tensile strength, hardness and modulus and decrease in elongation at break with nanographite loading, which can be attributed towards better CIIR–nanographite interaction. The above explanation was again verified from bound rubber measurements. It shows increase in bound rubber contents with nanographite loading. Dynamic mechanical analysis was used to study their relaxation behaviour as a function of temperature (?100 to 100°C) at frequency 1 Hz and 1% strain. The effect of increasing nanographite loadings on glass transition temperature was marginal in all the composites, and Tg value was in the range of ?10 to 10°C, which has been explained on the basis of relaxation dynamics of polymer chains in the vicinity of fillers. The effects of variation in nanographite loading and temperature on dynamic mechanical properties like loss tangent, storage and loss modulus have been reported. The effect of solvent (chloroform, benzene and tri-chloroethylene) on swelling properties at different periods of time (15, 30, 45 and 60 min) shows that the degree of swelling increases with time and decreases with concentration of nanographite loading.     

Preparation of MWCNT reinforced epoxy nanocomposite and examination of its mechanical properties

Abstract

Multiwalled carbon nanotube (MWCNT) reinforced and unfilled epoxy resins were prepared. Viscosity tests were run on the MWCNT filled and unfilled resins, comparative tensile, three point bending and Charpy impact tests were performed. The viscosity of MWCNT filled epoxy resin has increased by from three to one order of magnitude from the lowest to higher shear rate compared to unfilled epoxy. Owing to this, the simple cast specimen preparation was not applicable in the case of MWCNT filled epoxy; instead of that, a resin injection method was used. According to the results of the mechanical tests, tensile strength has decreased by 4·6% caused probably indirectly by nanotube filling of the resin, but Young's modulus, bending modulus and Charpy impact strength, which characterise resistance against dynamic loads, have increased by 12, 10 and 20% respectively.     

Influence of chlorinated paraffin on properties of silica filled polychloroprene

Abstract

Roles of the two widely used chlorinated paraffins, namely Cereclor S45 and Cereclor 48, in properties of silica filled polychloroprene were investigated. The results reveal that chlorinated paraffin significantly improves the processability. The improvement is more pronounced for Cereclor S45 due to its lower viscosity. However, the addition of chlorinated paraffin has a negative effect on cure. Owing to the reduction of crosslink density and the plasticising effect of chlorinated paraffin, several mechanical properties are impaired, e.g. tensile strength, modulus, hardness, abrasion resistance as well as rebound resilience. However, the deterioration of both tensile strength and modulus is not pronounced at low loading of chlorinated paraffin (≤8·0 parts per hundred of rubber, phr). Although chlorinated paraffin has little influence on the relative tensile strength, the relative 100% modulus is affected to a greater extent due to the combination of post curing retardation and evaporation of chlorinated paraffin during thermal aging.     

The Effect of Dicumyl Peroxide Vulcanization on the Properties & Morphology of Polypropylene/Ethylene-Propylene Diene Terpolymer/Natural Rubber Blends

ABSTRACT

This article discusses some properties such as tensile properties, chemical and oil resistance, gel content, crystallinity, and morphology of polypropylene (PP)/ethylene-propylene diene terpolymer (EPDM)/natural rubber (NR) blends. Dicumyl peroxide (DCP) was applied as a crosslinking agent. In terms of tensile properties, peroxide vulcanized blend shows higher tensile strength and tensile modulus (stress at 100% elongation, M₁₀₀) as compared with the unvulcanized blend. The elongation at break of the peroxide vulcanized blend is higher for the blend with NR rich content compared with the EPDM rich content. The improvements in chemical and oil resistance as well as gel content of peroxide vulcanized blends have also proved the formation of crosslinks in the rubber phase. Scanning electron microscopy (SEM) micrographs from the surface extraction of the blends support that the crosslinks have occurred during dynamic vulcanization. Dynamical vulcanization with DCP has decreased the percent crystallinity of blends that can be attributed to the formation of crosslinks in the rubber.     

Studies on the Tensile Properties of Rubberwood Fibre-Natural Rubber Composites

Abstract

Natural rubber (NR) composites were prepared by incorporating rubberwood fibres at different loadings into the NR matrix in a mixing mill according to a base formulation. Tensile properties, swelling measurement and tensile fracture surfaces of gum and composites with 0, 10, 20, 30 and 50 phr of rubberwood fibres were studied. Incorporation of rubberwood fibres in the composites increases the tensile modulus but reduces the tensile strength and elongation at break. Scanning electron microscopy (SEM) studies and swelling measurement indicate that the increasing rubberwood loading has weakened the rubber-filler interactions.     

Vulcanization characteristics and mechanical properties of natural rubber–scrap rubber compositions filled with leather particles

Scrap rubber recycling combined with waste leather particles in natural rubber compounds has been studied. The effect of leather and scrap rubber loading on vulcanization characteristics of natural rubber compounds has been evaluated. The presence of leather was found to reduce the scorch time and increase the maximum and minimum torque. While reversion was not observed in the absence of leather at 150 °C, it was more prominent when leather was incorporated. Mechanical properties such as tensile strength, elongation at break, tear strength, modulus and hardness were found to increase on increasing the scrap rubber loading in the absence of leather. Compounds containing leather exhibited higher tensile strength, modulus, hardness and tear strength values but the modulus and hardness values were found to decrease as the scrap rubber loading increased. All the vulcanizates exhibited only limited swelling in different media as the swelling of one phase of the composite was found to be restricted by the other phase. Copyright © 2004 Society of Chemical Industry     

Mechanical properties of wood-fiber/toughened isotactic polypropylene composites

This study investigates the mechanical properties of wood-fiber/toughened PP composite modified by physical blending with an EPDM rubber to improve impact toughness. Wood-fiber thermoplastic composites were prepared with a modified PP matrix resin, employing high shear thermokinetic compounding aided with maleated PP for the fiber dispersion. The addition of EPDM improved the impact toughness, while it reduced stiffness and strength properties. To compensate the non-plane strain fracture toughness, the specimen strength ratio (R_sb) was adopted as a comparative measure of fracture toughness. The strength ratio increased with the addition of EPDM, while it decreased with increasing wood-fiber concentration. The work of fracture increased with EPDM level except at large wood-fiber concentration. The effectiveness of the impact modification was assessed with the balance between tensile modulus and unnotched impact energy as a function of wood-fiber concentration. EPDM rubber modification was moderately effective for wood-fiber PP composites. The examination of fracture surfaces showed twisted fibers, fiber breakage, and fiber pull-out from the matrix resin.     

固相法氯磺化聚乙烯改性聚氯乙烯的研究

本文着重讨论了氯磺化聚乙烯（ＣＳＭ）的氯含量，硫含量以及ＣＳＭ的用量对聚氯乙烯（ＰＶＣ）增韧性能的影响。实验结果表明随ＣＳＭ中的氯含量、硫含量的增加．ＰＶＣ—ＣＳＭ共混体系的位伸强度增加，冲击强度下降；随ＣＳＭ加入量的增加，体系的拉伸强度下降，冲击强度上升。ＣＳＭ作为增韧剂改性ＰＶＣ可取得比ＰＶＣ─ＣＰＥ体系更好的效果。ＰＶＣ─ＣＳＭ体系可在其冲击强度满足工业生产要求的基础上最小限度的降低拉伸强度，使拉伸强度保持在９０％左右。