依溶解度系数制备高导电石墨烯/橡胶复合物

文章根据石墨烯、天然橡胶、甲苯及NMP 4种物质的汉森溶解度系数,设计出一套简便的石墨烯/天然橡胶复合材料制备方法。该方法先将石墨烯/NMP与天然橡胶/甲苯按一定比例混合,使甲苯/NMP混合溶液的溶解度系数与橡胶及石墨烯接近,使橡胶和石墨烯均能均匀地分散在混合液中;在接下来的开口搅拌过程中,随着甲苯的挥发,NMP/甲苯混合液的溶液度系数逐步向纯NMP溶液相偏离,致使橡胶分子夹带石墨烯片逐步自液体中析出而形成复合物。本方法操作简便,制备得到的复合材料导电性能优秀,石墨烯的渗透阈限在1%—1.5%。     

Flexible and stretchable electrode based on multiwalled carbon nanotube/deproteinized natural rubber composites

One of stretchable electronic devices is known as the compliant electrode which can retain good electrical conductivity under deformation. Compliant electrodes from MWCNTs and DPNR were prepared by using a UV‐curing process and Triton X‐100 as a dispersing agent. The effect of Triton X‐100/MWCNTs volume ratio was investigated by transmission electron microscopy indicating the highest dispersion was obtained at the volume ratio of 15.6. The mechanical and electrical properties were investigated by a melt rheometer in a tension mode. The 3%v/v MWCNTs composite possessed an excellent mechanical behavior (Young's modulus = 1.27 × 10⁶ Pa) and a high electrical conductivity (1.03 S/cm) relative to previous works. Under the same experimental conditions, a commercial compliant electrode named Danfoss exhibited the Young's modulus and electrical conducivity values of 7.56 × 10⁶ Pa and 2.54 × 10^?2 S/cm, respectively, which were inferior to the 3%v/v MWCNTs/DPNR. Moreover, the composite film still retained good electrical behaviors under 100% strain, high extentional strain rate of 1 s^?1, high flexed angle, and repeated stretching cycles (40% strain, 50 times) due to the intimate compatibility between the MWCNTs and the elastomer matrix. POLYM. ENG. SCI., 57:1356–1366, 2017. © 2017 Society of Plastics Engineers     

Probing the reinforcing mechanism of graphene and graphene oxide in natural rubber

Natural rubber (NR) containing graphene (GE) and graphene oxide (GO) were prepared by latex mixing. The in situ chemically reduction process in the latex was used to realize the conversion of GO to GE. A noticeable enhancement in tensile strength was achieved for both GO and GE filled NR systems, but GE has a better reinforcing effect than GO. The strain‐induced crystallization was evaluated by synchrotron wide‐angle X‐ray diffraction. Increased crystallinity and special strain amplification effects were observed with the addition of GE. The incorporation of GE produces a faster strain‐induced crystallization rate and a higher crystallinity compared to GO. The entanglement‐bound tube model was used to characterize the chain network structure of composites. It was found that the contribution of entanglement to the conformational constraint increases and the network molecular parameters changes with the addition of GE and GO, while GE has a more evident effect than GO. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Multifunctional and environmentally friendly nanocomposites between natural rubber and graphene or graphene oxide

This work describes a green route to multifunctional nanocomposite materials composed of natural rubber (NR) latex and graphene (rGO) or graphene oxide (GO). Aqueous solutions with different concentrations of GO and rGO (prepared with the surfactant cetyltrimethylammonium bromide – CTAB) were mixed with natural rubber latex under magnetic stirring followed by sonication. The slurries obtained after casting were dried in an oven in air at 70 °C for 24 h. The nanocomposites were characterized by TEM and SEM, AFM and KFM. The thermal, electrical and mechanical properties were evaluated using TGA, resistivity measurements (four-point) and DMA. Swelling tests were performed using three solvents with different polarities: xylene, isopropanol and water. The inclusion of filler networks in the polymeric matrices provided significant improvements in the electrical, chemical and mechanical properties, in comparison to the unfilled polymer. In addition, the nanocomposites proved to be biodegradable.     

Slow-release fertilisers based on natural rubber

It is estimated that only between 30-70% of the fertiliser applied in agriculture is used for plant nutrition, the rest is carried away by ground water or lost through nitrification-denitrification. Apart from the economic loss due to wastage, severe environmental problems arise due to increasing nitrate concentrations in public drinking water. The research reports a method of binding the fertiliser urea into natural rubber thus forming a matrix of rubber encapsulated fertiliser. A special ‘split-feeding’ mixing technique is necessary for a good product; also found important were mixing and vulcanisation temperatures with the optimum being in the 70?82°C range and 95°C respectively.     

氧化石墨烯/天然橡胶复合材料的制备与性能

采用己内酰胺（CPL）改性氧化石墨烯（GO）（CPL-GO）,与天然橡胶（NR）复合后通过熔融共混法制备了CPL-GO/NR复合材料。考察了CPL-GO用量对CPL-GO/NR复合材料物理机械性能、界面相互作用和气体阻隔性能的影响。结果表明,CPL改性GO后,X射线衍射层间距增加,片层堆砌更为松散,CPL-GO与水接触角增至91.2°。当CPL-GO的质量分数为2.0%时,CPL-GO/NR复合材料的拉伸强度为26.1 MPa,较纯NR提高了50.9%。随着CPL-GO用量的增加,复合材料的储能模量增加,损耗因子的峰值减小,表明GO经CPL表面改性后与NR复合,增强了两相界面间的相互作用,从而提高了复合材料抵抗变形的能力。在40 ℃下,当CPL-GO的质量分数为3.0%时,CPL-GO/NR复合材料的气体渗透系数较纯NR下降了57.1%。     

石墨烯基橡胶复合材料的制备与性能

综述了近年国内外石墨烯基橡胶复合材料的研究进展,主要包括石墨烯/天然橡胶复合材料、石墨烯/丁腈橡胶复合材料、石墨烯/丁苯橡胶复合材料、石墨烯/硅橡胶复合材料、石墨烯/丁基橡胶复合材料和石墨烯/异戊橡胶复合材料。同时对石墨烯基橡胶复合材料在制备和应用过程中遇到的难题进行了分析和总结。开发高质量石墨烯的绿色环保低成本制备和提纯技术以及提高石墨烯在橡胶中的有效分散效果将是今后该领域亟待解决的关键技术问题。     

石墨烯基橡胶复合材料的制备与性能

综述了近年国内外石墨烯基橡胶复合材料的研究进展,主要包括石墨烯/天然橡胶复合材料、石墨烯/丁腈橡胶复合材料、石墨烯/丁苯橡胶复合材料、石墨烯/硅橡胶复合材料、石墨烯/丁基橡胶复合材料和石墨烯/异戊橡胶复合材料。同时对石墨烯基橡胶复合材料在制备和应用过程中遇到的难题进行了分析和总结。开发高质量石墨烯的绿色环保低成本制备和提纯技术以及提高石墨烯在橡胶中的有效分散效果将是今后该领域亟待解决的关键技术问题。     

基于离子超分子网络实现自修复天然橡胶的制备

将甲基丙烯酸锌（ZDMA）或聚（甲基丙烯酸锌）低聚物（PM）引入到天然橡胶中,同时并用炭黑/白炭黑与天然橡胶共混,制备一种具有自修复性能的耐屈挠疲劳橡胶。研究结果表明,与PM相比,ZDMA可形成以离子交联为主的可逆超分子网络,赋予了硫化胶更好的自修复功能,当其用量为40份（质量）时硫化胶的自修复效率最高,接近100%。不饱和羧酸盐（ZDMA或PM）与传统填料（炭黑和白炭黑）并用时,PM仅在前期可有效抑制裂纹的扩展,ZDMA可明显提高材料的耐屈挠疲劳性能,当m（ZDMA）/m（炭黑）为20/40时硫化胶的耐屈挠疲劳性能最好。     

石墨烯基橡胶复合材料的研究进展

综述了近年石墨烯基橡胶复合材料的制备方法及研究成果,重点阐述了复合材料的热传导性、导电性以及气体阻隔性能方面的最新研究进展。同时对石墨烯基橡胶复合材料的发展前景进行了分析与展望,开发石墨烯表面化学修饰新方法和形态结构调控新工艺以及石墨烯基橡胶母料的高效、低成本制备技术将是该领域今后发展的主要方向。     

Study on the self-crosslinking behavior based on polychloroprene rubber and epoxidized natural rubber

This work has studied the impact of curing temperature and rubber compositions on the self-crosslinking behavior of the polychloroprene rubber (CR) and epoxidized natural rubber (ENR) blend. Variation of the temperature and blending ratios, rheological results have shown a better crosslinking result at 160°C with the optimum CR ratio at 75%. Then, Arrhenius equation was applied to verify the crosslinking kinetic and first-order kinetics has been verified. The chemical reaction routes proposed by differential scanning calorimetry have also been analyzed. Moreover, dynamic mechanical analysis and field emission scanning electron micrographs combined with energy-dispersive X-ray analysis were done to evaluate the phase compatibility. Based on the experimental results, a proposal “cross-promotion” reaction is drawn to conclude the self-crosslinking of CR and ENR. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Segmented block copolymers based on liquid natural rubber

Segmented block copolymers were prepared from hydroxyl-terminated liquid natural rubber (HTNR) and poly(ethylene oxide) (PEO). Toluene 2,4 diisocyanate (TDI) was used as the coupling agent for combining both types of segments. Keeping the molecular weight of HTNR constant, a series of materials were prepared using PEO with varying molecular weights. Their thermal and mechanical properties were evaluated. With increasing the PEO content, the properties vary from soft to rigid elastomers and rubber-toughened plastics. This variation in properties is caused by the changes in the sample morphology, which depends on the relative fractions of the hard and soft segments. Water absorption capability of these block copolymers was determined. Hydrogels with water content approximately up to 80% were obtained.     

Partial replacement of carbon black with graphene in natural rubber/butadiene rubber based tire compound: Investigation of critical properties

Journal of Polymer Research - In this study, we prepared graphene oxide-based styrene/acrylic elastomeric disks (GSAE) from sugarcane bagasse/ferrocene (GO) and styrene/acrylic emulsion (SAE) to...     

Vertically oriented polyaniline‐graphene nanocomposite based on functionalized graphene for supercapacitor electrode

Polyaniline functionalized reduced graphene oxide (PORGO) is prepared by interfacial polymerization and then vertically oriented polyaniline‐graphene (PANI‐PORGO) nanocomposites based on PORGO are developed successfully by in situ polymerization. The morphology and structure are characterized by field emission scanning electron microscopy (FE‐SEM), transmission electron microscopy (TEM), Fourier transform infrared spectra (FT‐IR), Raman spectra and X‐ray diffraction (XRD). The electrochemical tests indicate that the specific capacitance of PORGO and PANI‐PORGO is as high as 291 and 369 F/g, respectively, at the current density of 1 A/g. PANI—PORGO nanocomposite exhibits high electrochemical activity and enhanced cycle stability with a capacitance retention of 81.2% after 500 cycles at 10 A/g. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44808.     

Nanocomposites based on epoxidized poly(styrene-co-butadiene) rubber and graphene nanoplatelets

Nanofillers play as reinforcing agents of the polymer matrix. The reinforcement and dynamic mechanical properties of nanocomposites based on filled epoxidized-poly(styrene-co-butadiene) rubber are investigated. The modification of the polymer matrix allows improvement in polymer–filler interaction, and thus the mechanical properties of the vulcanizates. Here, the rubber was modified by introducing the epoxy functional groups in the matrix. The quantification for epoxidation rate was analyzed by means of NMR and ~8.8% epoxidation was optimized. The nanocomposites were prepared by melt-mixing technique. The influence of rubber epoxidation in enhancing dynamic mechanical and thermal properties was demonstrated. Stable filler networking using exfoliated graphene nanoplatelets (xg C750) and carbon black (CB-N234) in epoxidized rubber is described through multihysteresis measurements. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47802.     

Preparation and characterization of organoclay nanocomposites based on natural rubber

Rubber compounds based on natural rubber (NR) reinforced with octadecylamine‐modified bentonite have been prepared via a vulcanization process and characterized by several techniques. The silicate nanolayers are exfoliated and uniformly dispersed in the polymer chains. Monsanto measurements have shown that the organoclay accelerates the vulcanization reaction and, furthermore, gives rise to a marked increase of the torque, indicating that the elastomer becomes more crosslinked in the presence of the organoclay. These results were corrobated by swelling measurements since a noticeable increase in the curing degree was observed when the organoclay was added to the rubber recipe. Moreover, thermodynamic parameters have shown an increase in the structural order of the nanocomposite. In addition, thermal analysis supports the assumption that the degree of curing of the elastomer increases when the organoclay is added to the elastomer. An appreciable increase of the involved heat during the curing reaction has been observed. Moreover, the T_g of the NR increases in the presence of the organoclay due to the confinement of the elastomer segment into the organoclay nanolayers, which restricts the mobility of the chains. Copyright © 2003 Society of Chemical Industry     

Effect of epoxidised liquid natural rubber on nitrile/butadiene rubber based mixes

Abstract

Epoxidised liquid natural rubber (ELNR) constitutes a new family of polymers chemically derived from natural rubber. It is a highly viscous rubber of low molar mass generally used as plasticiser or processing aid, especially during processing of natural rubber and styrene/butadiene rubber stocks.

The effect of incorporating this polymer rather than a standard plasticiser in a nitrile/butadiene rubber based mix has been investigated. The retention in mechanical properties following air and oil aging of the vulcanisates was also studied. Satisfactory processability of compounded stocks, mechanical properties, and aging resistance was maintained following incorporation of ELNR into nitrile/butadiene rubber formulations even at the lowest plasticiser concentrations. The improvement in aging behaviour was more pronounced when 25 mol-% ELNR was used at concentrations above 15 pphr.     

Enhanced mechanical properties of graphene/natural rubber nanocomposites at low content

Graphene/natural rubber (GE/NR) nanocomposites were prepared by a modified latex mixing method combined with in situ chemical reduction. It was found that the GE nanosheets are well dispersed and have strong interfacial interaction with NR. Thus, adding a low content of GE can remarkably increase the tensile strength and the initial tensile modulus of NR. With incorporation of as low as 0.5 phr of GE, a 48% increase in the tensile strength and an 80% increase in the initial tensile modulus are achieved without sacrificing the ultimate strain. But further increasing the GE loading degrades the tensile strength and the ultimate strain. Dynamic mechanical measurement indicates that the storage modulus of the nanocomposites is greatly enhanced with addition of GE, while the loss tangent peak is depressed due to the reduced mobility of the rubber molecules. The reinforcement effect of GE on NR is interpreted as a change in the strain induced crystallization and network structure of the nanocomposites, based on the analysis of Mooney ? Rivlin plots and the tube model.© 2013 Society of Chemical Industry     

Studies on wood-to-wood bonding adhesives based on natural rubber latex

Natural rubber latex-based adhesives were prepared for wood-to-wood bonding. The effects of prevulcanization, and varying amounts of ammonium caseinate, carboxymethyl cellulose, cooked starch, and phenol formaldehyde resin on adhesion were studied. The water resistance of the bonds was tested in cold and hot water and was found to be superior compared with commercial latex-based adhesives.