Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Compatibilization of natural rubber (NR) and chlorosulfonated polyethylene (CSM) blends with zinc salts of sulfonated natural rubber
Kwanruethai Boonsong,Manus Seadan,Natinee Lopattananon
Songklanakarin Journal of Science and Technology , 2008,
Abstract: A rubbery ionomer of zinc salt of sulfonated natural rubbers (Zn-SNR) was synthesized and used as a new compatibilizerfor the blends of natural rubber (NR) and chlorosulfonated polyethylene (CSM). Epoxidized natural rubber (ENR)was also used for the preparation of NR/CSM blends. The effect of ionomer concentration on melt viscosity of the 50/50(%wt/wt) NR/CSM blends at different constant shear rates was characterized. It was found that the incorporation of ionomerincreased shear viscosity of the blends, indicating an increase in interfacial interaction between the NR and CSM. Themaximum shear viscosity was observed when the ionomer of 10% by weight of NR was added into the blends. The tensile,tear, oil resistant properties and morphology of the various 20/80 NR/CSM blends with and without the Zn-SNR and ENR atthe 10% wt of NR were examined. The 100% modulus, tensile strength, tear strength and oil resistance of the compatibilizedblends improved over those of the uncompatibilized blends. The blends compatibilized with the Zn-SNR showed higher levelsof improvement in modulus, tensile and tear strength than those of ENR. The tensile strength of 20/80 blends with the Zn-SNRand ENR compatibilizers increased by 38 and 30% over the corresponding neat blends. Furthermore, the addition of ionomerand ENR resulted in decreased domain of dispersed NR phase size and improved interfacial adhesion between the NR andCSM, indicating enhanced blend compatibility. These results suggest that the Zn-SNR is a new effective compatibilizer forNR and CSM blends.
Improved Automotive Fuel Resistance of Natural Rubber/Chlorosulfonated Polyethylene Blends by Blending Epoxidized Natural Polymer  [PDF]
Manisara Phiriyawirut, Sawanya Luamlam
Open Journal of Organic Polymer Materials (OJOPM) , 2013, DOI: 10.4236/ojopm.2013.34017

The natural rubber (NR) was mixed with chlorosulfonated polyethylene (CSM), due to the difference of polarity in NR and CSM made this blend incompatible and the third component was used. Epoxidzed natural rubber (ENR) was used as a third component. NR/CSM blended with the blend ratio of 50/50 was prepared by using a two-roll mill and vulcanization in a compression mold at 160°C. The ENR content was varied from 1 to 7 phr. The curing characteristics, morphology, mechanical properties, and automotive fuel swelling were investigated. The results indicated that the cure time of the blend rubbers was shorter as adding ENR. The mechanical properties of the blend rubbers were not affected by ENR content. However, automotive fuel resistance of the blend rubbers was found to increase with adding ENR in rubber blend.

Curing characteristics of chlorosulphonated polyethylene and natural rubber blends
Journal of the Serbian Chemical Society , 2005,
Abstract: The dependence of the Mooney scorch time and cure index on the blend ratio of chlorosulphonated polyethylene/natural rubber (CSM/SMR 20 CV) and chlorosulphonated polyethylene/chlorinated natural rubber (CSM/Pergut S 40) blends were determined in the temperature range from 120 oC to 160 oC using a Monsanto Mooney viscometer. Semi-efficient vulcanization systems were used for the study. The morphology of the fracture surface of the crosslinked systems was determined by Scanning Electron Microscopy (SEM). The results showed that the scorch time decreased with increasing SMR 20 CV and Pergut S 40 contents. This observation is attributed to the increasing solubility of sulfur, as the content of SMR 20 CV and Pergut S 40 in the composition increased. For temperatures greater than 140 oC, the dependence of the scorch time on blend ratios diminishes, as enough thermal energy is available to overcome the activation energy of vulcanization. The differing curing characteristics of the two blends is explained by the compatibility factor of the respective blend. Morphological analysis of the blends shows a very satisfactory agreement.
Diffusion Characteristics of Toluene into Natural Rubber/Linear Low Density Polyethylene Blends  [PDF]
Henry C. Obasi,Okoro Ogbobe,Isaac O. Igwe
International Journal of Polymer Science , 2009, DOI: 10.1155/2009/140682
Abstract: The sorption and diffusion of toluene through blends of natural rubber (NR) and linear low density polyethylene (LLDPE) of varying compositions were studied at 35, 55, and 65°C by conventional weight-gain experiments. The effects of blend ratio on the diffusion, sorption, and permeation coefficients were determined. The sorption data were used to estimate the activation energies of diffusion and permeation, parameters which were found to show a decrease when the amount of NR or LLDPE was increased. The transport of toluene through most of the blends was anomalous, althouh at 35°C, the transport of toluene through the 60/40 blend was Fickian and at 35°C, pseudo-Fickian. The enthalpy of sorption of toluene obtained is positive and suggests a Henry's type sorption.
Damping Properties of Ethylene-Vinyl Acetate Rubber/Polylactic Acid Blends  [PDF]
Xiaozhen He, Ming Qu, Xinyan Shi
Journal of Materials Science and Chemical Engineering (MSCE) , 2016, DOI: 10.4236/msce.2016.43003
Abstract: In this research, ethylene-vinyl acetate rubber (EVM)/polylactic acid (PLA) = 80/20 by weight blend was compounded with silica in a Haake torque rheometer. The effects of hindered phenol (AO-60), super branched polyol, petroleum resin C9, polyvinyl chloride (PVC) and acrylic rubber (ACM) on the damping properties of blends were investigated by dynamic mechanic analyzer (DMA). The results showed that 20 phr super branched polyol significantly increased the damping factor of PLA to widen the effective damping temperature range from 42.1to 102.5. 15 phr AO-60 and 10 phr petroleum resin C9 both dramatically raised the blend’s damping factor to broaden the effective damping temperature range to 98.0 and 102.6, respectively. ACM and PVC are compatible with EVM, and both improved the damping properties of EVM/PLA blends.
Study of the behavior of poly(vinyl chloride) and functionalized polyethylene blends
González,Jeanette; Rosales,Carmen; Hernández,Marianella; Ichazo,Miren;
Revista Técnica de la Facultad de Ingeniería Universidad del Zulia , 2007,
Abstract: in this research, blends of commercial poly(vinyl chloride) with linear low density polyethylenes (lldpe) and high density polyethylenes (hdpe) pure and functionalized were evaluated. different proportions of initiator (dicumyl peroxide-dcp) and 10 phr of a functionalizing agent (diethyl maleate-dem) were used in order to accomplish the functionalization of polyethylenes. the compounds were prepared in a twin screw extruder with a pvc/pe blend ratio of 65/35. the functionalization degree was determined by infrared spectroscopy (ftir). blends were characterized by differential scanning calorimetry (dsc) and by mechanical testing (tensile and impact strength); the morphology of the blends was also determined by scanning electron microscopy (sem). results obtained indicate that the functionalization of polyethylenes improves the processability of their blends with pvc. for the blends of pvc with lower k value and grafted lldpe with lower molecular weigth, not variation on the impact strength was obtained; samples more translucent were observed, as well as a reduction in the size of the structures in the disperse phase seen on the micrographs. this result seems to be closely related to the viscosity ratio of the components of these blends. concerning tensile properties a reduction in young?s modulus, tensile strength and elongation at break was found for all blends studied.
Processing and Characterization of High Density Polyethylene/Ethylene Vinyl Acetate Blends with Different VA Contents  [PDF]
Othman Y. Alothman
Advances in Materials Science and Engineering , 2012, DOI: 10.1155/2012/635693
Abstract: Different series of high density Polyethylene/Ethylene Vinyl Acetate (HDPE/EVA) blends were prepared via melt blending in a corotating intermeshing twin screw extruder. The effects of VA percentage and EVA loading ratio on the thermal, rheological viscoelastic, mechanical, and fracture toughness of the blends were analyzed. The results showed that the addition of EVA to HDPE reduces the thermal, elastic, and viscoelastic properties of the blends. The microscopic examination of the fracture surface confirmed the ductile fracture of HDPE/EVA blends for all blend ratios and VA percentages. Increasing the EVA ratio and VA content caused a significant reduction in the blend crystallinity but had no significant effect on melting temperature. The complex viscosity increased with increasing the percentage of EVA due to the restriction of molecular mobility and reduction of free volume, induced by the addition of EVA. The storage modulus decreased with increasing the EVA ratio and temperature, while it increased with increasing the frequency. Young’s modulus, yield strength, and fracture strain decreased with increasing the EVA ratio. Similarly, the fracture toughness decreased proportional to the EVA percentage. Finally the results indicated that the VA content has significant effects on the mechanical, thermal, and dynamic properties of HDPE/EVA blends. 1. Introduction Polyethylene (PE) is being increasingly used in many industrial and biomedical applications. Its outstanding features such as regular chain structure, combination of low cost and low energy demand for processing, excellent biocompatibility, and good mechanical properties make PE expand its application continuously [1–5]. The superiority of PE products over metal products is attributed to their light weight, high corrosion resistance, and low costs. However, there are some drawbacks with Polyethylene including low environmental stress cracking resistance, low creep resistance, and poor compatibility with various additives which restricted its use for cretin purposes [6, 7]. Therefore, there have been many attempts to improve the properties of polyethylene by blending it with organic or inorganic materials [6–14]. Among these materials is Ethylene Vinyl Acetate (EVA) copolymer, a member of the polyolefin family derived from random copolymerization of Vinyl Acetate (VA) and Ethylene. EVA properties vary substantially as a function of VA content [5]. The VA content has two main effects on polyethylene (PE). First, increasing VA content decreases the crystallinity of PE. Although PE crystallinity

QIN Chuan,YIN Jing-hua,HUANG Bao-tong,

高分子学报 , 1989,
Abstract: Compatibility of natural rubber (NR)/low density polyethylene blends was calculated and it was predicted that compatibility existed between the amorphous part of polyethylene and NR. Based on above calculation and prediction, an interaction model of polyethylene and NR was suggested. Effective network chain density measurement, dynamic mechanical spectrum measurement, wide angle X-ray diffraction and density measurement have been used to verify the compatibility of natural rubber/low density polyethylene blends (NR either unvulcanized or vulcanized) as predicted by the calculation and proposed model. Experimental results show that there exist certain interaction between amorphous LDPE and NR.
Non-isothermal crystallization kinetics of partially miscible ethylene-vinyl acetate copolymer/low density polyethylene blends
eXPRESS Polymer Letters , 2010, DOI: 10.3144/expresspolymlett.2010.19
Abstract: The non-isothermal crystallization kinetics of ethylene-vinyl acetate copolymer (EVA, 14 wt% vinyl acetate content), low density polyethylene (LDPE) and their binary blends with different blending ratio were investigated via differential scanning calorimetry. Jeziorny theory and Mo’s method were utilized in evaluating the crystallization behavior of both neat materials successfully. In the primary crystallization stage both EVA and LDPE had three-dimensional spherulitic growth mechanism. Apparently the crystallization rate of LDPE was faster than that of EVA at a low cooling rate. Increase in cooling rate limited the spherulites’ growth, which narrowed their rate difference. Influences from blending on the crystallization kinetics of each component in EVA/LDPE mixture were evaluated by Kissinger’s activation energy ( E) and Khanna’s crystallization rate coefficient (CRC). Inter-molecular interaction in the melt increased the E of both EVA and LDPE components at the beginning of cooling. During the primary crystallization stage of LDPE, dilution effect from EVA facilitated the crystal growth in LDPE. Co-crystallization between EVA component and the secondary crystallization stage of LDPE component also increased the CRC of EVA. In blend of EVA/LDPE = 7/3, LDPE obtained the maximal CRC value of 174.2 h–1. Results obtained from various approaches accorded well with each other, which insured the rationality of conclusion.

LU Yan,QIN Chuan,JING Xia-bin,HUANG Bao-tong,

高分子学报 , 1991,
Abstract: Two polyethylene/rubber blends, LLDPE/NR and LLDPE/SBR, were examined by FTIR-ATR spectroscopy and dynamic Tg measurements. It was found that the 835 cm-1 band of the NR and the 964cm-1 band of the SBR became higher and narrower as a result of blending with LLDPE, indicating certain extent of interaction between the amorphous molecular segments of PE and the rubber molecles. The Tg changes determined by dynamic techniques supported the result obtained by IR spectroscopy.
Page 1 /100
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.