Water-Swellable Thermoplastic Vulcanizates Based on Ethylene-vinyl Acetate Copolymer/Cross-linked Sodium Polyacrylate/Chlorinated Polyethylene

A novel water-swellable rubber (WSR) was prepared by dynamically vulcanizing ethylene-vinyl acetate copolymer (EVA)/chlorinated polyethylene (CPE) blends where the cross-linked poly (sodium acrylate) (CPNaAA) was used as a super water-absorbent resin and dispersed in the CPE rubber. Experimental results showed that the mechanical properties of TPVs decreased while the water-swelling ratio increased significantly with increasing of CPNaAA dosages, the swelling ratio of 60 phr CPNaAA TPVs reaching 746.1% at 93 h. Morphological study showed that the CPNaAA particles were dispersed randomly in the TPVs; Some significant gaps and large cavities could be found in the surface of dried TPVs.     

吸水膨胀型CM的结构及性能

采用交联聚丙烯酸钠(CPAAS)为吸水材料,制备了氯化聚乙烯橡胶(CM)/CPAAS共混型吸水膨胀橡胶(WSR),并对其力学性能、吸水性能、微观结构及粘弹行为进行了研究。结果表明,随着CPAAS用量的增加,WSR的吸水率显著提高,当CPAAS用量为60份时,室温条件下700h的吸水率高达1200%;2次及3次吸水率显著提高,失重率明显降低;FE-SEM观察表明,吸水干燥后,样品表面出现明显的孔洞,导致2次及3次吸水速率提高;粘弹行为研究表明,应变扫描时,WSR存在明显的Payne效应。     

聚氨酯/丁腈橡胶互穿网络型吸水膨胀橡胶的性能研究

将丁腈橡胶与高吸水树脂（SAP）、增强剂、聚乙二醇（PEG）和二苯基甲烷二异氰酸酯（MDI）等在开炼机上充分混合,在高温下PEG和MDI发生逐步聚合反应,与丁腈橡胶原位互穿,得到互穿网络型吸水膨胀橡胶（IPN-SWR）。研究了聚氨酯（PU）用量对互穿网络型吸水膨胀橡胶的机械性能和吸水膨胀性能的影响。结果表明,随着PU含量升高,橡胶的机械性能下降,吸水速率加快,最大质量膨胀倍率（ΔWe）先升高后降低,质量损失率降低,循环测试次数越高,膨胀性能下降,质量损失率变小。同种材料的胶筒制品的膨胀速率远远小于试片的膨胀速率。     

Adhesion Property of Benzoyl-Peroxide-Cured Epoxidized Natural Rubber/Acrylonitrile-Butadiene Rubber Blend Adhesives to Polyethylene Terephthalate Film

The loop tack, peel strength and shear strength of cross-linked epoxidized natural rubber (ENR-50)/acrylonitrile-butadiene rubber (NBR) blend adhesives were studied in the presence of coumarone-indene resin. Benzoyl peroxide was used as the cross-linking agent with dosage ranging from 1 to 5 parts per hundred rubber by weight (phr). Toluene was used as the solvent throughout the investigation. A SHEEN hand coater was used to coat the adhesive on a polyethylene terephthalate substrate at 60 and 120 μm coating thickness. The adhesive was cured at 80°C for 30 min prior to testing on a Lloyd adhesion tester operating at various testing rates from 10 to 60 cm min^?1. Results show that loop tack and peel strength of the ENR-50/NBR adhesives pass through a maximum value at 4 phr of benzoyl peroxide dosage. This observation is attributed to the increase in cohesive strength which culminates at 4 phr benzoyl peroxide loading. However, shear strength increases steadily with dosage of benzoyl peroxide due to the continuous increase in the cohesive strength as crosslinking of the rubber blend proceeds. In all cases, the adhesion properties increase with increasing coating thickness and testing rates.     

The Effect of Epoxidized Natural Rubber (ENR-50) or Polyethylene Acrylic Acid (PEA) as Compatibilizer on Properties of Ethylene Vinyl Acetate (EVA)/Natural Rubber (SMR L) Blends

The effect of epoxidized natural rubber (ENR) or polyethylene acrylic acid (PEA) as a compatibilizer on properties of ethylene vinyl acetate (EVA)/natural rubber (SMR L) blends was studied. 5 wt.% of compatibilizer was employed in EVA/SMR L blend and the effect of compatibilizer on tensile properties, thermal properties, swelling resistance, and morphological properties were investigated. Blends were prepared by using a laboratory scale of internal mixer at 120°C with 50 rpm of rotor speed. Tensile properties, thermal properties, thermo-oxidative aging resistance, and oil swell resistance were determined according to related ASTM standards. The compatibility of EVA/SMR L blends with 5 wt.% of compatibilizer addition or without compatibilizing agent was compared. The EVA/SMR L blend with compatibilizer shows substantially improvement in tensile properties compared to the EVA/SMR L blend without compatibilizer. Compatibilization had reduced interfacial tension and domain size of ethylene vinyl acetate (EVA)/natural rubber (SMR L) blends.     

Maleated Natural Rubber as a Coupling Agent for Recycled High Density Polyethylene/Natural Rubber/Kenaf Powder Biocomposites

Kenaf powder (KP) was incorporated into recycled high density polyethylene (rHDPE)/natural rubber (NR) blend using an internal mixer at 165°C and rotor speed of 50 rpm. The tensile strength and elongation at break of the composites decreased, while the tensile modulus increased with increasing filler loading. The water absorption was found to increase as the filler content increased. The maleic anhydride grafted natural rubber was prepared and used to enhance the composites performance. The addition of MANR as a coupling agent improved the tensile properties of rHDPE/NR/KP biocomposites. The water absorption was also reduced with the addition of MANR.     

Preparation of epoxidized acrylonitrile butadiene rubber and its compatibilization effect on water-swellable rubber composites

In this research, water-swellable rubbers (WSRs) were prepared by the blending of acrylonitrile butadiene rubber (NBR) with epoxidized acrylonitrile butadiene rubber (ENBR), precipitated silica, vulcanizing agents, and polyacrylic acid sodium (PAAS) as superabsorbent polymers (SAPs). ENBR was prepared with a molybdenum trioxide catalyst and a tert-butyl hydroperoxide oxidant through a free-radical reaction under specific conditions and was used as a compatibilizer to improve the interfacial adhesion of the NBR matrix and hydrophilic components of the WSRs. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy were used to analyze the structure and properties of ENBR. The dispersion of silica and SAPs in the rubber matrix was investigated by transmission electron microscopy. The presence of ENBR enhanced the water-absorption properties of the WSRs. The NBR–ENBR composites exhibited a higher mechanical performance after water absorption than that without ENBR. Both the swelling ratio and the absorption rate increased with the ENBR content. When the weight ratio of NBR–ENBR was 25/75, an equilibrium swelling ratio of 172% (13% higher than that of the sample without ENBR) was obtained. Scanning electron microscopy analysis revealed that the addition of ENBR improved the compatibility between the SAPs and the NBR matrix. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47694.     

动态硫化PSBR/PE共混型热塑性弹性体的研究

采用动态硫化法制备了粉末丁苯橡胶（PSBR）／聚乙烯（PE）共混型热塑性弹性体（TPO），研究了共混比、硫化体系、填料种类及用量、加工工艺对共混胶力学性能的影响。结果表明，当PSBR／PE共混比为60／40并采用传统硫化体系、白炭黑作补强剂时，TPO综合性能较好。     

耐盐型吸水膨胀丁腈橡胶的制备与性能

以丁腈橡胶为基胶、聚丙烯酸钠为吸水树脂(SAP)、乙二胺四乙酸二钠(EDTA -2 Na)为金属离子封闭剂,与聚乙二醇和二苯基甲烷二异氰酸酯混合物共混制得耐盐型吸水膨胀橡胶(WSR),分别考察了聚氨酯(PU)生成量、EDTA -2 Na和聚丙烯酸钠用量对WSR物理机械性能及矿化度水中吸水膨胀性能的影响.结果表明,随着P...     

Preparation of dynamically vulcanized thermoplastic elastomer nanocomposites based on LLDPE/reclaimed rubber

Dynamically vulcanized thermoplastic elastomers nanocomposites (TPV nanocomposites) based on linear low density polyethylene (LLDPE)/reclaimed rubber/organoclay were prepared via one‐step melt blending process. Maleic anhydride grafted polyethylene (PE‐g‐MA) was used as a compatibilizing agent. The effects of reclaimed rubber content (10, 30, and 50 wt %), nanoclay content (3, 5, and 7 wt %), and PE‐g‐MA on the microstructure, thermal behavior, mechanical properties, and rheological behavior of the nanocomposites were studied. The TPV nanocomposites were characterized by X‐ray diffraction, transmission electron microscopy, scanning electron microscopy (SEM), differential scanning calorimeter, mechanical properties, and rheometry in small amplitude oscillatory shear. SEM photomicrographs of the etched samples showed that the elastomer particles were dispersed homogeneously throughout the polyethylene matrix and the size of rubber particles was reduced with introduction of the organoclay particles and compatibilizer. The effects of different nanoclay contents, different rubber contents, and compatibilizer on mechanical properties were investigated. Increasing the amount of nanoclay content and adding the compatibilizer result in an improvement of the tensile modulus of the TPV nanocomposite samples. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

线性双峰聚乙烯／低密度聚乙烯共混物的流变行为与力学性能

研究了线性双峰聚乙烯（LBPE）与低密度聚乙烯（LDPE）共混物溶体的流变行为，讨论了共混物的组成，剪切应力和剪切速率以及温度对熔体流变行为，熔体粘度的影响，测定了不同配比熔体的非牛顿指数（n)，熔体流动速率（MFR）及力学性能，为双峰聚乙烯的加工和使用提供了理论依据。     

Effects of Dynamic Vulcanization and Acrylic Acid on Properties of Recycled Poly(vinyl chloride)/Acrylonitrile Butadiene Rubber (PVCr/NBR) Blends

Effects of dynamic vulcanization and acrylic acid (AAc) on processability, mechanical properties, swelling behavior, morphology, and thermal stability of recycled poly(vinyl chloride)/acrylonitrile butadiene rubber (PVCr/NBR) blends were investigated. Blends were prepared in a Haake Rheomix at a temperature of 150°C and a rotor speed of 50 rpm. Recycled poly(vinyl chloride)/acrylonitrile butadiene rubber (PVCr/NBR) blends were also prepared as comparison. It was found that the dynamic vulcanization and the addition of acrylic acid improved the stabilization torque, mechanical energy, stress at peak, stress at 100% elongation (M₁₀₀), swelling resistance, and thermal stability but decreased the elongation at break of the blends. The introduction of a cross-link into the elastomer phase and better compatibility between PVCr and NBR are responsible for the enhancement of thermal stability and mechanical properties of dynamically vulcanized PVCr/NBR + AAc as evidence from the scanning electron microscopy (SEM) of the tensile fracture surfaces and infrared spectroscopy study of the dynamically vulcanized of PVCr/NBR + AAc shows.     

Compatibilization Effects of PE-g-MA on Mechanical,Thermal and Swelling Properties of High Density Polyethylene/Natural Rubber/Thermoplastic Tapioca Starch Blends

Effect of polyethylene grafted maleic anhydride (PE-g-MA) on mechanical, thermal and swelling characteristic of high density polyethylene (HDPE)/natural rubber (NR)/thermoplastic tapioca starch (TPS) blends were studied. The measurements from differential scanning calorimetric (DSC), dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA), proved the effectiveness of PE-g-MA as compatibilizer in improving the miscibility between HDPE/NR – TPS blends. A decrement in crystallinity index was found after adding PE-g-MA. It is due to restriction in mobility of the HDPE chains. In the presence of PE-g-MA, the blends have better thermal stability. On top of that, the storage modulus which is reflected to the blend stiffness also increased as indicated the improvement in HDPE/NR – TPS interaction.     

PROPERTIES OF POLYPROPYLENE/NATURAL RUBBER/RECYCLE RUBBER POWDER BLENDS

Thermoplastic elastomers have been prepared by blending polypropylene (PP), natural rubber (NR), and recycle rubber powder (RRP). The blends were melt-mixed using a Brabender Plasticorder torque rheometer at 190°C and 50 rpm. A fixed 70:30 blend ratio (wt%) of PP and rubber was prepared. The effect of partial replacement of NR with RRP at a fixed rubber content (NR+RRP), 30 wt% on mechanical properties, swelling behavior, torque development, and morphological properties of PP/NR/RRP blends was studied. Results show that the tensile strength, Young's modulus, and swelling resistance increase with increasing RRP content in the PP/NR/RRP blends whereas the stabilization torque and elongation at break exhibit opposite trend.     

CPE-g-PEG在CPE/P(AA-AM)吸水膨胀弹性体中的增容作用

选择自制的吸水树脂丙烯酸/丙烯酰胺共聚物(P(AA-AM))与氯化聚乙烯(CPE)为共混原料,以CPE-g-PEG两亲性接枝共聚物为增容剂,机械共混制备了增容型吸水膨胀弹性体(WSE).对共混物的亚微形态、吸水膨胀特性以及力学性能进行了研究.TEM结果表明简单共混时,CPE/P(AA-AM)共混物试样的相容性差.添加CPE-g-PEG后CPE与P(AA-AM)相间有一定程度的连接.接枝物的加入,改善了共混试样的重复使用情况,降低了其质量损失率,提高了WSE的稳定性,改善了试样的力学性能,接枝物加入量为6份时,拉伸强度最大.     

Effect of Testing Rate on Adhesion Properties of Benzoyl-Peroxide-Cured ENR 25/NBR Blend Adhesive Using Gum Rosin and Coumarone-Indene Resin as Tackifiers

Dependence of adhesion properties of benzoyl-peroxide-cured epoxidized natural rubber (ENR 25)/acrylonitrile-butadiene rubber (NBR) blend adhesive on testing rate was systematically studied. Coumarone-indene resin and gum rosin were used as tackifiers. Toluene was used as solvent throughout the study. The SHEEN hand coater was used to coat the adhesive on polyethylene terephthalate at 30 and 120 µm coating thickness. The adhesion properties were measured by a Lloyd adhesion tester operating at different rates of testing. Results showed that the loop tack, peel strength, and shear strength increased with increasing testing rate, an observation that was attributed to the viscoelastic nature of adhesive. In all cases, the adhesion properties of the adhesives also increased with increasing coating thickness.     

Heat Shrinkable Behaviour of Supramolecular Hydrogen Bonded Maleated Ethylene Propylene Diene Rubber and Maleated High Density Polyethylene Blend

Maleated high density polyethylene and maleated ethylene propylene diene rubber (50 wt%/50 wt%) was blended in presense of 3-amino-1,2,4-triazole (ATA). The supramolecular hydrogen bonding was characterized by FTIR and dynamic mechanical analysis. The crystallinity of the blend system was studied by XRD and it was observed that supramolecular hydrogen bonding decreases the crystallinity of the blend. The supramolecular hydrogen bonded network improves heat shrinkability of the blend.     

Effects of zinc borate loading on thermal stability,flammability, crystallization properties of magnesium oxide/(90/10) mLLDPE/(NR/ENR-50) blends

Effects of different zinc borate (ZB) loadings on thermal, flammability and crystallinity properties of blends of 10 % rubber (9/1) natural rubber (NR)/epoxidised natural rubber (ENR)/metallocene linear low density polyethylene/N,N-m-phenylenebismaleimide/MgO were investigated. Fourier transform infrared spectroscopy revealed that –C=O and –OH groups appeared while C–O–C and C=C groups disappeared in all blend samples. ZB increased the activation of HVA-2 by changing the reaction mechanism and increasing the concentration of the –C=O groups in the blends due to the peak at 1,714–1,718 cm^?1. The crystallinity of all blends was increased by ZB loading increase; therefore, it played the heterogeneous nucleation center and maximum crystallinity was observed at 6 phr ZB blend. The thermal stability of NR improved with increase of zinc borate loading and the highest thermal stability was determined for 8 phr ZB blend. Good compatibilization between the two rubbers (NR/ENR-50) was achieved in the presence of ZB, which was revealed by the presence of only one peak for their decomposition. The limiting oxygen index value of mLLDPE was decreased by two rubbers loading increase, while it was increased by ZB loading increase to provide fire barriers to protect flammable materials from thermal damage. It was concluded that ZB has a synergistic effect on the LOI values of flame retardant mLLDPE/rubber containing MgO.     

Preparation and Properties of Ethylene-vinyl Acetate/linear Low-density Polyethylene/Graphene Oxide Nanocomposite Films

Ethylene-vinyl acetate-based nanocomposites with 18 and 28 wt% vinyl acetate were prepared via solution casting method. To improve the mechanical and barrier properties of ethylene-vinyl acetate, linear low-density polyethylene, and graphene oxide were introduced to matrix. The morphological studies indicated that the graphene oxide diffraction peak disappeared in all prepared nanocomposites, probably due to its exfoliation; also proper dispersion and good interaction between nanofillers and polymer matrix were achieved. By introducing low amount of graphene oxide into the matrix, the mechanical and thermal properties and oxygen permeability were improved especially for those with 28 wt% vinyl acetate monomer.     

Mechanical and Electrical Properties of Jute Fabrics Reinforced Polyethylene/Polypropylene Composites: Role of Gamma Radiation

Jute fabrics reinforced polyethylene (PE), polypropylene (PP) and mixture of PP+PE matrices based composites (50 wt% fiber) were prepared by compression molding. It was found that the mixture of 80% PP + 20% PE hybrid matrices based jute fabrics reinforced composites performed the best results. Gamma radiation (250–1000 krad) was applied on PP, PE and jute fabrics then composites were fabricated. The mechanical properties of the irradiated composites (500 krad) were found to increase significantly compared to that of the non irradiated composites. Electrical properties like dielectric constant, loss tangent and conductivity with temperature variation of the composites were studied.