Thermal,morphological, and physicomechanical properties of (chlorinated polyethylene rubber)/(chloroprene rubber) blends

The effect of the blend ratio on the thermal, morphological, and physicomechanical properties of (chlorinated polyethylene rubber)/(chloroprene rubber) (CPE/CR) blends was studied. Two distinct glass transition temperatures (T_g) of all blends were observed in differential scanning calorimetry curves, falling between the T_g of the two pure rubbers. Analysis of the blends by scanning electron microscopy showed both dispersed and continuous phase morphology that depended on the blend composition. Thermogravimetric analysis showed that all the compounds underwent two stages of thermal degradation. The Mooney viscosity and optimum cure times increased with the increase in CPE contents, whereas the scorch times decreased. The tensile strength and elongation at break decreased, whereas the 100% modulus, hardness, and compression set increased with the increase of CPE content; the tear strength had the lowest value for the 50/50 CPE/CR blend because of the poor miscibility. The results from thermal aging and oil resistance tests showed that pure CPE possessed better thermal aging property and oil resistance than those of pure CR. Thus, considerable improvement in oil resistance of the blend compounds was achieved with the increase of CPE content. J. VINYL ADDIT. TECHNOL., 21:18–23, 2015. © 2014 Society of Plastics Engineers     

Study of the orientation‐controlled damping temperature based on selective distribution of oligo‐phenol in acrylate rubber/chlorinated butyl rubber blends

In this paper, a series of composites containing of the oligo‐phenol (produced by reacting of 4‐methyl‐phenol with dicyclopentadiene and isobutylene (MPDI)) as organic fillers, and chlorinated butyl rubber (CIIR)/acrylate rubber (AR) as matrix were prepared by melting blending method. The selective distribution phenomenon of organic fillers in the matrix and the damping properties of AR/CIIR/MPDI composites were characterized by DMA, DSC, FT‐IR and SEM, respectively. The results showed that MPDI could form hydrogen bond with AR more easily than with CIIR, which resulted in MPDI dispersing preferentially in AR phase in CIIR/AR composites. And the selective dispersion of MPDI caused that the damping temperature range was orientedly broadened towards the high temperature. Specially, with the content of MPDI increased to 10 wt% in AR/CIIR marix, only the T_g of AR in AR/CIIR composites shifted to higher temperature, which reached to 55.2°C, while the T_g and T_ll of CIIR in AR/CIIR composites kept almost unchanged. Otherwise, the temperature range of AR/CIIR/MPDI was expanded to 100.2°C with the tan δ > 0.3. Therefore, it was expected as a promising way to orientedly broaden damping temperature range according to the selective distribution of organic additives in binary systems. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Mechanical properties,oil resistance,and thermal aging properties in chlorinated polyethylene/natural rubber blends

The use of natural rubber (NR) for partly substituting elastomeric chlorinated polyethylene (CPE) was determined. Mechanical and thermal aging properties as well as oil resistance of the blends were also investigated. The amount of NR in blends significantly affected the properties of the blends. The blends with NR content up to 50 wt % possessed similar tensile strength to that of pure CPE even after oil immersion or thermal aging. Modulus and hardness of the blends appeared to decrease progressively with increasing NR content. These properties also decreased in blends after thermal aging. After oil immersion, hardness decreased significantly for the blends with high NR content, whereas no change in modulus was observed. The dynamic mechanical properties were determined by dynamic mechanical thermal analysis. NR and CPE showed damping peaks at about ?40 and 4 °c, respectively; these values correlate with the glass‐transition temperatures (T_g) of NR and CPE, respectively. The shift in the T_g values was observed after blending, suggesting an interfacial interaction between the two phases probably caused by the co‐vulcanization in CPE/NR blends. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 22–28, 2002; DOI 10.1002/app.10171     

In situ compatibilization of low-density polyethylene and polydimethylsiloxane rubber blends using ethylene–methyl acrylate copolymer as a chemical compatibilizer

The effect of the ethylene–methylacrylate copolymer as a chemical compatibilizer in the 50:50 blend of low-density polyethylene (LDPE) and polydimethylsiloxane rubber (PDMS) has been studied in detail. Ethylene–methylacrylate (EMA) reacted with PDMS rubber during melt-mixing at 180°C to form EMA-grafted PDMS rubber (EMA-g-PDMS) in situ, which acted as a compatibilizer in the LDPE–PDMS rubber blend. An optimum proportion of the compatibilizer (EMA) was found to be 6 wt % based on results of dynamic mechanical analysis, adhesion studies, and phase morphology. Lap shear adhesion between the phases increased significantly on incorporation of 6 wt % of EMA. Dynamic mechanical analysis showed a single glass transition (T_g) peak at ?119°C. This was further supported by X-ray diffraction studies, which exhibited a remarkable increase in the degree of crystallinity and phase morphology and showed a drastic reduction in the size of the dispersed phase at the optimum concentration of EMA. © 1993 John Wiley & Sons, Inc.     

Viscoelastic changes in chlorinated butyl rubber modified with graphene oxide

The glass–rubber transition region in multiple component systems is significant for studying the slow relaxation processes in amorphous polymers. It is the first time that graphene oxide (GO) is added into chlorinated butyl rubber (CIIR) to study the effect of GO on different relaxation processes of CIIR. We aimed to give a possible insight to the molecular relaxation behaviors of CIIR/GO nanocomposites. In this study, GO was synthesized by a revised Hummers method, and it was incorporated with CIIR at different contents of 0, 1, 2, 3 and 5 phr (parts per hundred rubber). The structure of GO and CIIR/GO nanocomposites was studied by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared (ATR-FTIR), scanning electron microscopy (SEM) and transmission electron microscope (TEM).Bound rubber was adopted to study the interfacial interaction between GO and CIIR. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were also performed. Since there were many conflicting results on the effect of nanoparticles in relation to the glass transition temperature (T _g) of polymer matrixes in correlative literature, we investigated the effect of GO on that of CIIR. The T _g determined by DSC shows slight shifting. However, the maximum and the shoulder of tan δ both shift to low temperatures. In addition, GO increases the coupling effect of CIIR, resulting the shoulder merged with the maximum. A mechanism, though still needs to be further refined, has been proposed to interpret the contradictory results in our case.     

Mechanical properties,flame retardancy,hot‐air ageing,and hot‐oil ageing resistance of ethylene‐vinyl acetate rubber/hydrogenated nitrile‐butadiene rubber/magnesium hydroxide composites

The mechanical properties, flame retardancy, hot‐air ageing, and hot‐oil ageing resistance of ethylene‐vinyl acetate rubber (EVM)/hydrogenated nitrile‐butadiene rubber (HNBR)/magnesium hydroxide (MH) composites were studied. With increasing HNBR fraction, elongation at break and tear strength of the EVM/HNBR/MH composites increased, whereas the limited oxygen index and Shore A hardness decreased slightly. Hot‐air ageing resistance and hot‐oil ageing resistance of the composites became better with increasing HNBR fraction. Thermal gravimetric analysis results demonstrated that the presence of MH and low HNBR fraction could improve the thermal stability of the composites. Differential scanning calorimeter revealed that the glass transition temperature (T_g) of the composites shifted toward low temperatures with increasing HNBR fraction, which was also confirmed by dynamic mechanical thermal analysis. Atomic force microscope images showed MH has a small particle size and good dispersion in the composites with high HNBR fraction. The flame retardancy, extremely good hot‐oil ageing, and hot‐air ageing resistance combined with good mechanical properties performance in a wide temperature range (?30°C to 150°C) make the EVM/HNBR/MH composites ideal for cables application. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Thermal behavior of natural rubber and chlorinated rubber blends

A solid-state chemical reaction occurs when a solvent cast film of a blend of masticated natural rubber and chlorinated natural rubber is heated in the presence of air at 150°C. The thermal behavior of solvent cast films of chlorinated natural rubber, masticated natural rubber, and a 1 : 1 w/w blend (2% w/v in xylene) of these two polymers has been studied using differential scanning calorimetry, infrared spectroscopy, scanning electron microscopy, and nuclear magnetic spectroscopy. The results suggest that carbonyl groups are incorporated into the blend on heating and that the vinyl functionality of the isoprene units is modified during this apparent oxidation. Heating for 2 h at 150°C results in a material that no longer contains the rubber-like cis-1,4-polyisoprene units. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 1379–1384, 1997     

Preparation and characterization of hyperbranched polymer modified montmorillonite/chlorinated butyl rubber damping composites

In this work, Na⁺‐montmorillonite (MMT) was modified by hyperbranched polymer (HBP) and grafted with hindered phenol to improve the damping and other properties of the chlorinated butyl rubber (CIIR) composites. The hyperbranched polymer‐modified montmorillonite (HBP‐OMMT) was prepared by organic montmorillonite (OMMT) that was obtained from the cation exchange reaction between MMT and silane quaternary ammonium salt. The main characterization methods were Fourier transform infrared spectroscopy, hydrogen nuclear magnetic resonance, X‐ray diffraction, scanning electron microscopy, energy dispersive spectrometer, and thermogravimetric (TG) analysis. The basal spacings of MMT, OMMT, and HBP‐OMMT were 1.47, 2.94, and 4.09 nm, respectively. The onset and center temperatures of decomposition (T_?5% and T_max) of HBP‐OMMT were improved from 301 and 369 °C to 332 and 398 °C, respectively. The CIIR damping composites were prepared by mechanical blending of HBP‐OMMT with pure CIIR. The tensile strength and elongation at break of the composites were improved from 5.4 MPa and 890% to 7.6 MPa and 1066%. From TG curves, T_?5% and T_max were increased from 297.4 and 406.0 °C to 323.3 and 410.5 °C, respectively. The dynamic mechanical analysis results showed that tan δ rose from the original 1.20 to 1.44 with the addition of HBP‐OMMT. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43645.     

Miscibility of some chlorinated poly(hydrocarbons) with ethylene-acrylic rubber

The compatibility of an ethylene-acrylic rubber (R) with poly (chloroprene) (CR) and two chlorinated poly-ethylenes, containing 48 (CPE 48) and 25 (CPE 25) wt.-% chlorine, was investigated. Blends with the latter polymer were studied in the complete composition range. The techniques used were phase-contrast microscopy, differential scanning calorimetry, dynamic mechanical and stress-strain testing. The single T_g relaxation of blends and its almost linear variation with composition, together with results obtained using the techniques mentioned, support the view that the systems are miscible at the segmental level. At low rubber contents an antiplasticisation effect was observed for the R/CPE 25 system. At high rubber compositions a small reduction of crystallinity and a melting point depression of the PE phase in CPE were observed. Various equations proposed to predict the T_g of blends and their modulus using pure component data were also tested at varying compositions and temperatures.     

Effect of imidazolium ionic liquid type on the properties of nitrile rubber composites

We investigated the influence of hydrophilic and hydrophobic imidazolium ionic liquids on the curing kinetic, mechanical, morphological and ionic conductivity properties of nitrile rubber composites. Two room temperature ionic liquids with a common cation—1‐ethyl‐3‐methylimidazolium thiocyanate (EMIM SCN; hydrophilic) and 1‐ethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM TFSI; hydrophobic)—were used. Magnesium–aluminium layered double hydroxide (MgAl‐LDH; also known as hydrotalcite) was added to carboxylated acrylonitrile–butadiene rubber (XNBR) whereas fumed silica Aerosil 380 was used in acrylonitrile–butadiene rubber (NBR) as reinforcing fillers. NBR compounds were vulcanized with a conventional sulfur‐based crosslinking system whereas XNBR compounds were cured with MgAl‐LDH. The optimum cure time reduction and tensile properties improvement were obtained when both ionic liquids were added at 5 parts per hundred rubber (phr). The results revealed that EMIM SCN and EMIM TFSI induced an increase in the AC conductivity of nitrile rubber composites from 10^?10 to 10^?8 and to 10^?7 S cm^?1, respectively (at 15 phr ionic liquid concentration). The presence of ionic liquids in NBR slightly affected the glass transition temperature (T_g) whereas the presence of EMIM TFSI in XNBR contributed to a shift in T_g towards lower temperatures from ?23 to ?31 °C, at 15 phr loading, which can be attributed to the plasticizing behaviour of EMIM TFSI in the XNBR/MgAl‐LDH system. Dynamic mechanical analysis was also carried out and the related parameters, such as the mechanical loss factor and storage modulus, were determined. © 2013 Society of Chemical Industry     

Influence of oil contents in dynamically cured natural rubber and polypropylene blends

Mechanical, dynamic, thermal, and morphological properties of dynamically cured 60/40 NR/PP TPVs with various loading levels of paraffinic oil were investigated. It was found that stiffness, hardness, tensile strength, storage shear modulus, complex viscosity, glass transition temperature (T_g) of the vulcanized rubber phase, degree of crystallinity and crystalline melting temperature (T_m) of the polypropylene (PP) phase decreased with increasing loading levels of oil. This is attributed to distribution of oil into the PP and vulcanized rubber domains causing oil‐swollen amorphous phase and vulcanized rubber domains. An increasing trend of elastic response in terms of tension set and damping factor was observed in the TPVs with loading levels of oil in a range of 0–20 phr. It is supposed that a major proportion of oil was first preferably migrated into the PP phase and caused an abrupt decreasing trend of degree of crystallinity and T_m of the PP phase. The dispersed vulcanized rubber domains remained small as particles with a low degree of swelling. Increasing loading levels of oil higher than 20 phr caused a decreasing trend of elongation at break and elastomeric properties. Saturation of oil in the PP phase was expected and the excess oil was transferred to the rubber phase which thereafter caused larger swollen vulcanized rubber domains. The remaining amount of oil was able to separate as submicron pools distributed in the PP matrix. This caused lowering of T_g, T_m, crystallinity of PP phase as well as strength, elastomeric, and dynamic properties of the TPVs. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Miscibility of chlorinated polymers with epoxidized natural rubber II. Blends with chlorinated polypropylene and with poly(vinylidene chloride-alkyl acrylate) copolymer

The compatibility of epoxidized natural rubber (at the 50 mol-% oxirane level) (ENR) with chlorinated polypropylene (CPP) and a poly(vinylidene chloride) copolymer (PVDCC) was investigated in the complete composition range. Phase-contrast microscopy revealed microheterogeneities attributed to the existence of gel particles in the solution-cast films. A more uniform phase distribution was obtained in hotpressed films. Dynamic mechanical spectroscopy and DSC results indicated that both systems are miscible at the segmental level. Ultimate elongation increases at significant (>50 wt.-%) ENR levels. The blend modulus dependence on composition supports the view that synergistic effects are present. These can be explained by postulating the existence of intermolecular interactions predicted using suitable models proposed to interpret the compositional variation of T_g.     

Effects of fillers,maleated ethylene propylene diene diene rubber,and maleated ethylene octene copolymer on phase morphology and oil resistance in natural rubber/nitrile rubber blends

The phase morphology and oil resistance of 20/80 NR/NBR blends filled with different types of fillers and copolymers were investigated. In the case of filler effect, N220, N330, and N660 carbon blacks with different particle sizes were used. Additionally, the blends filled with nonblack‐reinforcing fillers, that is, precipitated and silane‐treated silica, were investigated. To study the compatibilization effect, maleated ethylene propylene diene rubber (EPDM‐g‐MA) and maleated ethylene octene copolymer (EOR‐g‐MA) were added to the blends. The results revealed that the addition of filler, either carbon black or silica, to the blend caused a drastic decrease in NR dispersed phase size. Carbon blacks with different particle sizes did not produce any significant difference in NR dispersed phase size under the optical microscope. Silica‐filled blends showed lower resistance to oil than did the carbon black–filled blends. In addition, it was determined that neither EOR‐g‐MA nor EPDM‐g‐MA could act as a compatibilizer for the blend system studied. The oil resistance of the blends with EPDM‐g‐MA is strongly affected by the overall polarity of the blend. In the case of EOR‐g‐MA, the oil resistance of the blends is significantly governed by both overall polarity of the blend and phase morphology. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1156–1162, 2003     

Miscibility in poly(vinyl chloride)/chlorinated poly(vinyl chloride) blends,and blends of different chlorinated poly(vinyl chlorides)

Blends of poly(vinyl chloride) with chlorinated poly(vinyl chloride) (PVC), and blends of different chlorinated poly(vinyl chlorides) (CPVC) provide an opportunity to examine systematically the effect that small changes in chemical structure have on polymer-polymer miscibility. Phase diagrams of PVC/CPVC blends have been determined for CPVC's containing 62 to 38 percent chlorine. The characteristics of binary blends of CPVC's of different chlorine contents have also been examined using differential calorimetry (DSC) and transmission electron microscopy. Their mutual solubility has been found to be very sensitive to their differences in mole percent CCl₂ groups and degree of chlorination. In metastable binary blends of CPVC's possessing single glass transition temperatures (T_g) the rate of phase separation, as followed by DSC, was found to be relatively slow at temperatures 45 to 65° above the T_g of the blend.     

Influence of ZnO nanoparticles on the cure characteristics and mechanical properties of carboxylated nitrile rubber

Zinc oxide (ZnO) nanoparticles assembled in one dimension to give rod‐shaped morphology were synthesized. The effect of these ZnO nanoparticles (average particle size ～ 50 nm) as the curing agent for carboxylated nitrile rubber was studied with special attention to cure characteristics, mechanical properties, dynamic mechanical properties, and swelling. These results were compared with those of the conventional rubber grade ZnO. The study confirmed that the ZnO nanoparticles gave a better state of cure and higher maximum torque with a marginal decrease in optimum cure time and scorch time. The mechanical properties also showed an improvement. There was an increase in tensile strength by ～ 120%, elongation at break by ～ 20%, and modulus at 300% elongation by ～ 30% for the vulcanizate cured with ZnO nanoparticles, as compared with the one containing rubber grade ZnO. Dynamic mechanical analysis revealed that the vulcanizates exhibited two transitions—one occurring at lower temperature due to the T_g of the polymer, while the second at higher temperature corresponding to the hard phase arising due to the ionic structures. The second transition showed a peak broadening because of an increase in the points of interaction of ZnO nanoparticles with the matrix. The tan δ peak showed a shift towards higher T_g in the case of ZnO nanoparticle‐cured vulcanizate, indicating higher crosslinking density. This was further confirmed by volume fraction of rubber in the swollen gel and infrared spectroscopic studies. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Effect of phenol functionalization of carbon nanotubes on properties of natural rubber nanocomposites

This paper reports the results of studies on the effect of phenol functionalization of carbon nanotubes (CNTs) on the mechanical and dynamic mechanical properties of natural rubber (NR) composites. Fourier transform infrared spectrometry (FTIR) indicates characteristic peaks for ether and aromatic rings in the case of phenol functionalized CNT. Although differential scanning calorimetric (DSC) studies show no changes in the glass‐rubber transition temperature (T_g) of NR in the nanocomposites due to surface modification of CNT, dynamic mechanical studies show marginal shifting of T_g to higher temperature, the effect being pronounced in the case of functionalized CNT. Stress‐strain plots suggest an optimum loading of 5 phr CNT in NR formulations and the phenolic functionalization of CNT does not affect significantly the stress‐strain properties of the NR nanocomposites. The storage moduli register an increase in the presence of CNT and this increase is greater in the case of functionalized CNT. Loss tangent showed a decrease in the presence of CNT, and the effect is more pronounced in the case of phenol functionalized CNT. Transmission electron microscopy (TEM) reveals that phenol functionalization causes improvement in dispersion of CNT in NR matrix. This is corroborated by the increase in electrical resistivity in the case of phenol functionalized CNT/NR composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

A study about the structure of vulcanized natural rubber/styrene butadiene rubber blends and the glass transition behavior

A study of the thermal behavior of cured elastomeric blends of natural rubber (NR) and styrene butadiene rubber (SBR) prepared by solution blending in toluene is presented. Binary blends with different compositions of NR/SBR were produced using a conventional cure system based on sulfur and TBBS (n-t-butyl-2-benzothiazole sulfonamide as accelerator. The compounds were vulcanized at 433 K up to an optimum time of cure determined by rheometric tests. From swelling tests, the crosslink densities of the compounds were obtained and compared with those obtained in similar blends prepared by mechanical mixing. The results were analyzed in terms of the disentangling of the chain structures of the SBR and NR phases and the achieved cure state of the blend. Using differential scanning calorimetry, the glass transition temperature T_g of each blend was measured. In most compounds, the value of T_g corresponding to each phase of the blend was determined, but in some blends a single value of T_g was obtained. The variation of T_g with the composition and cure level in each phase was analyzed. On the other hand, a physical mixture of two equal parts of NR and SBR vulcanized was measured and the results were compared to those of the NR50/SBR50 cured blend. Besides, to analyze the influence of the network structure, pure NR and SBR unvulcanized samples were measured. On the basis of all the obtained results, the influence of the interphase formed in the blend between SBR and NR phases is discussed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Mechanical properties and fracture behaviors of epoxy composites with phase‐separation formed liquid rubber and preformed powdered rubber nanoparticles: A comparative study

Epoxy composites filled with phase‐separation formed submicron liquid rubber (LR) and preformed nanoscale powdered rubber (PR) particles were prepared at different filler loading levels. The effect of filler loading and type on the rheological properties of liquid epoxy resin suspensions and the thermal and mechanical properties of the cured composites as well as the relative fracture behaviors are systematically investigated. Almost unchanged tensile yield strength of the cured epoxy/PR composites is observed in the tensile test compared with that of the neat epoxy; while the strength of the cured epoxy/LR composites shows a maximum value at ∼4.5 wt% and significantly decreases with increasing LR content. The glass transition temperature (T_g) of the cured PR/epoxy has shifted to the higher temperature in the dynamic mechanical thermal analysis compared with that of the cured pure epoxy and epoxy/LR composites. Furthermore, the presence of LR results in highly improved critical stress intensity factor (K_IC) of epoxy resin compared with the corresponding PR nanoparticles. In particular, the PR and LR particles at 9.2 wt% loading produce about 69 and 118% improvement in K_IC of the epoxy composites, respectively. The fracture surface and damage zone analysis demonstrate that these two types of rubber particles induce different degrees of local plastic deformation of matrix initiated by their debonding/cavitation, which was also quantified and correlated with the fracture toughness of the two epoxy/rubber systems. POLYM. COMPOS., 36:785–799, 2015. © 2014 Society of Plastics Engineers     

Effect of plasticizer and curing system on freezing resistance of rubbers

At glass transition temperature, T_g the rubber compound becomes stiff and brittle and it loses all its rubbery characteristics. This article deals with the changes in T_g of rubber blends based on natural rubber and polybutadiene rubber of varying vinyl content having different types and content of plasticizers, different curing systems and its effect on physico‐mechanical properties to improve its freezing resistance. The plasticizers used were dioctylphthalate (DOP), tricrecylphosphate (TCP), dioctyladipate (DOA), and oil type plasticizers like parafinic oil (P#2) and aromatic oil (A#2). Among the plasticizers, when DOP and DOA content was high, an appreciable decrease of T_g was found compared to TCP. Moreover, there was a remarkable decrease of T_g using DOA plasticizer, which shows more effective on freezing resistance. However, there was not much change in T_g with oil‐type plasticizers with high oil content compared to TCP plasticizer. The effect of cross‐linking systems such as conventional sulfur vulcanization (CV), efficient sulfur vulcanization (EV), and dicumyl peroxide (DCP) and rubber blends with varying vinyl content in polybutadiene rubber were also carried out. It was found that T_g in different cross‐linking system decreased in this order: CV < EV < DCP. It reveals that DCP cross‐linking system affect more for improving freezing resistance. Physico‐mechanical properties such as tensile strength, tear strength, hardness were also measured. The ratio of initial slope (M₀) to steady‐state slope (M₁), M₀/M₁ in tensile curves of different blends were verified, which in turn related to the physico‐mechanical properties and freezing resistance of rubber compounds. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39795.     

Preparation and properties of heat curable blended methylfluorosilicone rubber

Heat curable blended methylfluorosilicone rubber (MFSR) was prepared by combination of methylsilicone rubber (MSR) and fluorosilicone rubber (FSR). 2,5‐Bis(tert‐butylperoxy)‐2,5‐dimethylhexane (DBPMH) was chosen as a curing agent. Poly(methylsiloxane‐co‐fluorosiloxane) with low molecular weight was used as an interfacial agent. Curing characteristics, mechanical properties, low temperature performance, and hot oil resistance of blended MFSR was studied in details. The results showed that MSR and FSR could reach co‐vulcanization by DBPMH in blended MFSR. Higher FSR content could improve the scorch safety, lower the rate of curing reaction, and lead to the poor processability of blended MFSR. An increase of FSR content also improved the hot oil resistance of blended MFSR. Interfacial agent could limit the phase separation of MSR and FSR, make the blended system more thermodynamically stable and elevate the mechanical properties of blended MFSR. Differential scanning calorimetry (DSC) measurements revealed that increasing MSR content lowered the glass transition temperature (T_g) and improved the low‐temperature flexibility of blended MFSR when MSR was no more than 15%. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers