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Influence of Poly(vinyl chloride) on Natural Rubber/Chlorosulfonated Polyethylene Blends  [PDF]
Manisara Phiriyawirut, Sawanya Luamlam
Open Journal of Organic Polymer Materials (OJOPM) , 2013, DOI: 10.4236/ojopm.2013.34013
Abstract:

Blend of natural rubber (NR) and chlorosulfonated polyethylene (CSM) was so interesting due to binding of the good oil resistance of CSM, the good mechanical properties and low cost of NR. However, due to the different polarities of two rubbers, phase separation and inferior properties of NR/CSM blend were obtained. The practical way to improve its properties is the addition of the third component to bind both phases of the blend. Effects of poly(vinyl chloride), PVC as compatibilizer on cure characteristics, morphology, mechanical properties and automotive fuel resistance of NR/ CSM blend were investigated. In this contribution, NR/CSM blend with blend ratio of 50/50 was prepared using a two-roll mill, and then vulcanized in a compression mold at 160°C. The PVC content was varied from 1 to 7 phr. It was found that the usage of 7 phr PVC led to improve interaction between NR and CSM phases. Therefore, increase in cure characteristics, mechanical strength and automotive fuel resistance of the blend was observed.

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.
STUDIES ON REACTIVE COMPATIBILIZATION AND DYNAMIC VULCANIZATION OF POLYPROPYLENE/EPOXIDIZED NATURAL RUBBER BLENDS FILLED WITH CARBONIZED DIKA NUTSHELL  [PDF]
G.N.Onyeagoro1,M.E.Enyiegbulam
Academic Research International , 2012,
Abstract: Carbonized Dika nutshell filled – polypropylene (PP)/epoxidized natural rubber (ENR) blend was prepared and its morphological, rheological and mechanical properties were studied. A combination of maleic anhydride-modified PP (PP-g-MA) and poly (lactic acid) (PLA) was used as compatibilizer, which act as interfacial agents between PP and ENR phases. The effectiveness of compatibilization was suggested from viscosity and storage modulus, determined by rheological measurements. Compatibilization produced increases in complex viscosity, storage modulus and impact strength. Dynamic vulcanization also resulted in increases in these properties, which were higher than those observed for noncompatibilized/ non-vulcanized blends. The increase in complex viscosity, storage modulus and impact strength with compatibilization and vulcanization is due to molecular build-up arising from chemical reactions that occurred during the melt blending process, as well as increase innetwork formation caused by vulcanization. Outstanding mechanical performance, especially tensile strength and impact strength (higher values), and elongation at break (lower values) were obtained with increase in filler content.
Development of SBR-Nanoclay Composites with Epoxidized Natural Rubber as Compatibilizer  [PDF]
R. Rajasekar,Gert Heinrich,Amit Das,Chapal Kumar Das
Journal of Nanotechnology , 2009, DOI: 10.1155/2009/405153
Abstract: The significant factor that determines the improvement of properties in rubber by the incorporation of nanoclay is its distribution in the rubber matrix. The simple mixing of nonpolar rubber and organically modified nanoclay will not contribute for the good dispersion of nanofiller in the rubbery matrix. Hence a polar rubber like epoxidized natural rubber (ENR) can be used as a compatibilizer in order to obtain a better dispersion of the nanoclay in the matrix polymer. Epoxidized natural rubber and organically modified nanoclay composites (EC) were prepared by solution mixing. The nanoclay employed in this study is Cloisite 20A. The obtained nanocomposites were incorporated in styrene butadiene-rubber (SBR) compounds with sulphur as a curing agent. The morphology observed through X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) shows that the nanoclay is highly intercalated in ENR, and further incorporation of EC in SBR matrix leads to partial exfoliation of the nanoclay. Dynamic mechanical thermal analysis showed an increase in storage modulus and lesser damping characteristics for the compounds containing EC loading in SBR matrix. In addition, these compounds showed improvement in the mechanical properties.
Cure and physical properties of natural rubber and epoxidized natural rubber compounds using various types of accelerators
Nakason, C.,Sainumsai, W.,Kaesaman, A.,Klinpituksa, P.
Songklanakarin Journal of Science and Technology , 2003,
Abstract: Cure characteristics and tear properties of epoxidized natural rubber (ENR-33) and natural rubber were studied. Three types of accelerators, namely 2-mercaptobenzothiazole (MBT), 2-morpholinothiobenzothiazole (MBS) and N-tert-butyl-2-benzothiazyl sulphenamide (TBBS) were used in this work. The conventional valcanization (CV) system was used. Cure characteristics were determined using a Monsanto Oscillating Disk Rheometer (ODR 2000) at 150oC. Also, a systematic study of tear strength was carried out before and after ageing at 70oC for 72 h. A Hounsfield tensometer (Model H10KS) operating at 500 mm/min was used to determine the tear strength using standard angle test pieces. The results indicated that scorch time and cure time of natural rubber are greater than those of ENR-33 compounds. However, the contrary was observed for the minimum and maximum torques and the torque differences. The observation is attributed to the activation of a double bond by the adjacent epoxide group in ENR-33. Furthermore, we found that the change in tear strength of aged ENR sample was greater than that of NR vulcanizates.
SORPTION CHARACTERISTICS OF DYNAMICALLY VULCANIZED POLYPROPYLENE/EPOXIDIZED NATURAL RUBBER BLENDS FILLED WITH CARBONIZED DIKA NUTSHELL (Irvialgia Gabonensis).  [PDF]
Onyeagoro1,M.E.Enyiegbulam
Academic Research International , 2012,
Abstract: The sorption characteristics of dynamically vulcanized polypropylene/epoxidized natural rubber blends filled with carbonized Dika nutshell have been investigated with specialreference to the effects of filler carbonization temperature and dosage of cross-linking agent. Toluene, an aromatic solvent commonly used in the rubber industry, was chosen as the solvent in this investigation. The filled blends were prepared by compression moulding using maleic anhydride-graft-polypropylene as a compatibilizer. The blend morphology was studied using Scanning Electron Microscope (SEM). Both the SEM and dynamic vulcanization studies indicate that the non-compatibilized/ non-vulcanized blends are immiscible and form twophase structures, accompanied by high solvent (toluene) uptake. Resistance to toluene sorptionincreased with increase in the dosage of cross-linking agent due to increase in cross-link density as a result of increase in network formation. This behaviour is supported by SEM micrographs of vulcanized and non-vulcanized blends, which reveal restriction to swelling of vulcanized blends due to increase in network formation. Resistance to toluene sorption with increase in filler carbonization temperature was also observed. This is attributed to increasein surface area of the filler due to the elimination of volatile matter that are deleterious to the blend-filler interfacial interaction.
Adhesion property of epoxidized natural rubber (ENR)-based adhesives containing calcium carbonate
eXPRESS Polymer Letters , 2008, DOI: 10.3144/expresspolymlett.2008.48
Abstract: The adhesion property (i.e. viscosity, loop tack and peel strength) of epoxidized natural rubber (ENR 25 and ENR 50 grade)-based pressure-sensitive adhesive was studied in the presence of calcium carbonate. The range of calcium carbonate loaded was from 10 to 50 parts per hundred parts of rubber (phr). Coumarone-indene resin was used as the tackifier and its concentration was fixed at 80 phr. Toluene was chosen as the solvent throughout the investigation. The substrates (PET film/paper) were coated with the adhesive using a SHEEN hand coater at a coating thickness of 60 μm. Viscosity of the adhesive was measured by a HAAKE Rotary Viscometer whereas loop tack and peel strength were determined by a Llyod Adhesion Tester operating at 30 cm/min. Results show that viscosity of ENR-based adhesives increases gradually with increase in calcium carbonate loading due to the concentration effect of the filler. However, for loop tack and peel strength, it passes through a maximum at 30 phr calcium carbonate, an observation which is attributed to the optimum wettability of adhesive on the substrate at this adhesive composition. ENR 25-based adhesive consistently exhibits higher adhesion property than ENR 50 for all calcium carbonate loadings studied.
Development of Biobased Poly(Lactic Acid)/Epoxidized Natural Rubber Blends Processed by Electrospinning: Morphological, Structural and Thermal Properties  [PDF]
Jaqueline G. L. Cosme, Vanessa M. Silva, Regina R. C. Nunes, Paulo H. S. Picciani
Materials Sciences and Applications (MSA) , 2016, DOI: 10.4236/msa.2016.74021
Abstract: This article reports the production of electrospun fibers from blends of poly(lactic acid) (PLA) and epoxidized natural rubber (ENR) solutions. The produced fibers were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). SEM images showed the reduction in fiber size with ENR content of up to 25% in the mixture PLA/ENR. FTIR analysis revealed a possible interaction between carboxylic group of PLA and epoxi group of ENR. Thermal analysis showed the increase of the crystallinity fraction with ENR content and a decrease in thermal stability of eletrospun mats with the addition of ENR. The dynamic mechanical properties showed an enhancement of the stiffness of PLA/ENR blends with the increase of ENR content, which can support the production of interesting materials for tissue engineering based on renewable and biocompatible polymers. The reported properties indicate the possibility to use such fiber mats as potential materials in tissue engineering.
EFFECT OF ZINC OXIDE LEVEL AND BLEND RATIO ON VULCANIZATE PROPERTIES OF BLEND OF NATURAL RUBBER AND ACRYLONITRILE-BUTADIENE RUBBER IN THE PRESENCE OF EPOXIDIZED NATURAL RUBBER
G. N. Onyeagoro
Academic Research International , 2012,
Abstract: Effect of Zinc Oxide level and blend ratio on vulcanizate properties of natural rubber (NR)/acrylonitrile-butadiene rubber (NBR)/epoxidized natural rubber (ENR) blend was studied. NR/NBR/ENR vulcanizates with compositions of 100/100/0 ; 100/90/10 ; 100/70/300 ; 100/50/50 ; 100/30/70 ; and 100/10/90 wt. %, respectively were each prepared with Zinc Oxide level of 0, 2.0, 4.0, 5.0, 6.0, 7.0, and 8.0 phr. The effect of Zinc Oxide level and blend ratio on tensile strength, modulus, elongation at break, hardness, abrasion resistance, compression set, and swelling behaviour of the vulcanizates were investigated. Results obtained show that the use of lower or higher than recommended level of Zinc Oxide in rubber vulcanization can lead to inferior or poor quality vulcanizate. Zinc Oxide level of 5.0 phr gave vulcanizates with optimum tensile strength, modulus and abrasion resistance. Further addition of Zinc Oxide was accompanied by a steady decrease in these properties. Of all blend systems studied, blend sample with composition NR/NBR/ENR: 100/70/30 produced the highest value of these properties. Hardness and compression set showed an increasing trend with increase in Zinc Oxide level due to increase in crosslink density; whereas elongation at break decreased with increase in Zinc Oxide level for the same reason. All vulcanizates exhibited a decreasing trend in swelling ratio as Zinc Oxide level increased up to 5.0 phr, and then increased with further increase in Zinc Oxide. The values of Gibbs free energy (ΔG) and volume fraction of NR in all vulcanizates studied increased with increase in Zinc Oxide level, reaching a maximum at 5.0 phr Zinc Oxide. This signifies progressive improvement in the interfacial interaction between blend components. These interactions lead to an increase in the effective degree of crosslinking, which improves the mechanical properties of the vulcanizates.
A Structural Study of Epoxidized Natural Rubber (ENR-50) and Its Cyclic Dithiocarbonate Derivative Using NMR Spectroscopy Techniques  [PDF]
Rosniza Hamzah,Mohamad Abu Bakar,Melati Khairuddean,Issam Ahmed Mohammed,Rohana Adnan
Molecules , 2012, DOI: 10.3390/molecules170910974
Abstract: A structural study of epoxidized natural rubber (ENR-50) and its cyclic dithiocarbonate derivative was carried out using NMR spectroscopy techniques. The overlapping 1H-NMR signals of ENR-50 at δ 1.56, 1.68–1.70, 2.06, 2.15–2.17 ppm were successfully assigned. In this work, the 13C-NMR chemical shift assignments of ENR-50 were consistent to the previously reported work. A cyclic dithiocarbonate derivative of ENR-50 was synthesized from the reaction of purified ENR-50 with carbon disulfide (CS2), in the presence of 4-dimethylaminopyridine (DMAP) as catalyst at reflux temperature. The cyclic dithiocarbonate formation involved the epoxide ring opening of the ENR-50. This was followed by insertion of the C–S moiety of CS2 at the oxygen attached to the quaternary carbon and methine carbon of epoxidized isoprene unit, respectively. The bands due to the C=S and C–O were clearly observed in the FTIR spectrum while the 1H-NMR spectrum of the derivative revealed the peak attributed to the methylene protons had split. The 13C-NMR spectrum of the derivative further indicates two new carbon peaks arising from the >C=S and quaternary carbon of cyclic dithiocarbonate. All other 1H- and 13C-NMR chemical shifts of the derivative remain unchanged with respect to the ENR-50.
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