微波加热技术在橡胶硫化中的应用研究

本文针对橡胶微波加热硫化所存在的问题,应用ANSYS有限元分析软件,在分析比较了传统加热硫化和微波加热硫化胶料温升特点的基础上,提出了微波间歇加热的方法。根据硫化历程,设计了间歇加热的流程图,并模拟分析了微波间歇加热硫化胶料的温度变化趋势,模拟结果显示：采用微波间歇加热硫化能有效的解决微波连续加热硫化升温过快、焦烧时间不足、胶料不能很好充满模型,以及胶料内外温差逐渐加大的问题,对实际工程具有一定的实用价值。     

微波预热过程中胶料焦烧的原因及解决措施

介绍微波预热胶料技术的特点和常见问题。针对微波预热胶料的焦烧问题进行分析,指出影响微波预热胶料焦烧的因素主要有橡胶品种、配方、预成型胶料形状、微波炉设备、温度控制、预热功率及时间。使用微波预热可缩短胶料在模具中的预热时间,改善硫化胶质量,提高生产效率。     

微波在橡胶工业中的应用

简述了微波加热的原理和特点,介绍了微波技术在国内橡胶工业中的应用,主要包括微波硫化、微波脱硫、微波干燥天然橡胶,最后对微波技术在橡胶加工中存在的问题和发展方向进行了展望。     

超声波在废橡胶再生中的应用

全世界每年要产生1000多万吨的废旧橡胶,对环境构成了严重的污染,废橡胶作为一种宝贵的资源被再生利用具有重要的意义。再生橡胶的制造方法很多,如油法、水油法、快速搅拌脱硫法、连续挤出脱硫法及微波脱硫法等。但它们均存在一定的缺点。新近出现的超声波脱硫法具有高效、环保、产品质量高等优点,已受到广泛关注。超声波利用声空化作用可将能量集中于分子键的局部位置,这种局部能量会产生惊人的效果,破坏硫化胶中能量比C-C键低的C-S键和S-S键,从而有选择的破坏橡胶三维网络结构,而不是大分子键断裂。为此人们进行了大量的试验,并发明了…     

密炼机工艺对废胎胶粉脱硫效果的影响

研究了密炼机再生工艺对废旧轮胎胶粉再生效果的影响。对再生橡胶的交联密度、溶胶含量、门尼黏度、物理机械性能和动态力学性能进行了分析。结果表明,溶胶含量随着脱硫温度的升高而逐渐增大;交联密度随着脱硫温度的升高而逐渐降低;根据horikx理论分析表明高混脱硫再生工艺再生过程中化学键的断裂以交联键断裂为主。再生胶的焦烧时间(ts 1)和再硫化时间(t9 0)随着脱硫温度的升高均呈现逐渐增大的趋势,拉伸强度随脱硫温度的增加逐渐降低。随脱硫时间的增加,再生胶硫化胶的拉伸强度略有降低,拉断伸长率变化不大。     

橡胶材料硫化技术的研究进展

硫化工序是决定橡胶制品质量的关键。文章介绍了橡胶硫化领域的技术演进,其主要包括传统的化学热硫化、新兴的微波硫化及辐射硫化的原理、特点和发展历程,并将它们进行比较,与传统硫化方法相比,微波及辐射硫化技术作为橡胶硫化领域的新兴技术日益得到关注与重视。     

防焦剂的发展和应用

一、前言胶料在贮存和加工成型过程中受热的作用,发生早期硫化(交联)并失去流动性能和再加工的能力,这就是所谓焦烧现象。胶料的焦烧是橡胶加工过程中常见的问题之一。特别是近年来致力于生产过程的强化(快速密炼、快速压出和压延,高速硫化等)以及采用易引起焦烧的材料,如细粒子炭     

一种橡胶脱硫的方法及其装置

由马如琦申请的专利（专利号CN1908042,公开日期2007—02—07）“一种橡胶脱硫的方法及其装置”,提供了一种橡胶脱硫方法：将硫化胶经粉碎、筛选和磁选后,再经过微波炉进行微波脱硫,脱硫后的胶料由微波炉出料口直接进入挤出机喂料口,通过挤出机进行塑化、降温和过滤,制得产品。该发明优点是生产效率高、成本低、还原效果好、适应范围广,且整个生产过程环保效果好。     

河北瑞威科技有限公司

正橡胶循环利用专家助剂生产设备制造技术服务常温常压橡胶再生还原剂RV系列-适用于硫磺硫化体系的硫化橡胶和焦烧胶料RDS系列-适用于非硫磺硫化体系的硫化橡胶和焦烧胶料包括:NR BR SBR NBR EPDM CR IIR FPM ACM橡胶加工助剂橡胶分散剂、橡胶流动剂、橡胶内脱模剂、橡胶隔离剂     

再生橡胶在三角带底胶中的应用

通过再生橡胶与天然橡胶/丁苯橡胶并用共混探究了再生橡胶的用量及硫化体系对三角带底胶各项性能的影响。结果表明,并用少量再生橡胶,不会影响产品的物理性能,但是其焦烧时间和正硫化时间会变短;随着再生橡胶用量的增大,尤其是当其用量超过70份时,产品拉伸、耐磨等性能有所下降,撕裂性能增加,弹性稍有下降。当并用50~70份再生橡胶时,可以在不降低产品性能的基础上降低成本。改变硫化体系发现,使用硫黄/2,2′-二硫代二苯并噻唑/N-(氧化二亚乙基)-2-苯并噻唑次磺酰胺(S/DM/NOBS)并用效果最好,有合适的焦烧时间和正硫化时间,且综合性能较好。     

Friction and wear behavior of styrene butadiene rubber‐based composites reinforced with microwave‐devulcanized ground tire rubber

In this work, the tribological properties of a new material obtained by revulcanization with styrene butadiene rubber (SBR) and devulcanized ground tire rubber (GTR) were investigated. GTR was devulcanized using the microwave method at a constant power while varying the microwave exposure time. Devulcanized rubber (DV‐R) and untreated GTR were revulcanized by mixing with SBR at different rates (10, 30, 50 phr). To determine friction and wear characteristics of the samples, pin (ball) on disc and abrasion tests were conducted. Scanning electron microscopy (SEM) was employed to observe the worn surfaces of the composites to correlate the experimental test results to the wear mechanisms. All of these tests and experiments were performed on original vulcanized rubber samples for comparison. The composites exhibited different friction and wear behavior due to morphology, dispersion behavior and devulcanization functionalization of ground tire rubber. In general, DV‐R/SBR composites exhibited improvement in both mechanical and tribological properties. However, the enhanced compatibility of DV‐R resulting from the specific chemical coupling of DV‐R with SBR was crucial for the mechanical, friction and wear properties. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42419.     

Effects of processing parameters on the properties of microwave‐devulcanized ground tire rubber/polyethylene dynamically revulcanized blends

This work aimed to evaluate the effects of processing parameters on properties of dynamically revulcanized blends based on 60 wt % of devulcanized ground tire rubber (GTR) and 40 wt % of high density polyethylene (HDPE). Devulcanization of the GTR was carried out in a system comprised of a conventional microwave oven adapted with a motorized stirring system with speed control. The resulting devulcanized GTR contained 26 wt % soluble in toluene. It was processed with HDPE in a twin screw extruder to produce a dynamically revulcanized blend. Processing parameters such as screw speed and feeding mode were varied. Their effects were evaluated based on tensile, dynamic mechanical, thermal and rheological properties, as well as on morphology. The results show the importance of the processing parameters involved in the production of blends with dynamically revulcanized rubber phase in the extruder, and good match between the residence time of the rubber and its revulcanization kinetics. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43503.     

Continuous ultrasonic devulcanization of carbon black‐filled NR vulcanizates

The continuous ultrasonic devulcanization of natural rubber (NR) filled with various concentrations of carbon black (CB) indicated a minimum of crosslink density and gel fraction at an intermediate amplitude, which is independent of CB content. An attempt was made to improve the efficiency of devulcanization by use of various chemicals (1,3 Diphenylguanidine, 2‐Mercaptobenzothiazole, Thianaphthene). However, these experiments did not indicate any improvement in comparison with devulcanization without chemicals. An idea of adding fresh CB into devulcanized compound, which has been shown to improve mechanical properties in the case of styrene–butadiene rubber (SBR), was tested in the present study for CB filled NR compound. The obtained result indicated that an addition of fresh CB to devulcanized CB‐filled NR did not lead to an improvement in mechanical properties upon revulcanization. The revulcanization recipe was optimized to improve the mechanical properties of revulcanized CB‐filled NR vulcanizates. It was found that CB‐filled NR upon revulcanization retained its strain‐induced cystallizability with the tensile strength and elongation at break at about 50 and 70% level of the virgin vulcanizates. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2340–2348, 2001     

The role of devulcanizing agent for mechanochemical devulcanization of styrene butadiene rubber vulcanizate

More or less universally, bis(3‐triethoxysilyl propyl) tetrasulfide (TESPT) has been used as a coupling agent during dispersion of silica filler in a virgin nonpolar rubber compound. It is for the first time that TESPT has been used as a devulcanizing agent and as‐grown devulcanized rubber facilitates the silica dispersion in nonpolar rubber compound without any coupling agent. Dual functionalities of TESPT have been modeled and validated in this work. Various factors like the role of sol‐gel content, inherent viscosity of sol rubber, crosslink density, and degree of devulcanization were investigated as a function of devulcanization time and amount of TESPT to optimize devulcanization time and TESPT amount. To study the silica reinforcement, revulcanization of devulcanized SBR was carried out with silica filler and the curing characteristics of the material were evaluated. From the mechanical properties and thermogravimetry analysis the optimum time for devulcanization is determined. Further, scanning electron microscopy (SEM) studies were undertaken to check the coherency and homogeneity of the material. POLYM. ENG. SCI., 58:74–85, 2018. © 2017 Society of Plastics Engineers     

Thiosalicylic acid as a devulcanizing agent for mechano-chemical devulcanization

A mechano-chemical devulcanization process for vulcanized natural rubber (NV) was investigated. Thiosalicylic acid was used as a test devulcanizing agent in comparison to diphenyl disulfide as the reference. The optimum condition for devulcanization of NR vulcanizates (NVs) was found to be grinding of the NV and subsequent mixing with a selected devulcanizing agent at 140°C for 30 min. The degree of devulcanization was indicated by using sol-gel fractions of the devulcanized rubber (DVR). Revulcanized rubber was made by using virgin natural rubber (NR) containing DVR at different ratios. The tensile strength of the DVR/NV composite, after revulcanization, decreased by 5–10%, while the elongation at brake was improved by 5–10% at a DVR content of 5–15%. Devulcanization of industrial truck tires, as a typical sample of industrial products, was also demonstrated for the practical application of this technique.     

Devulcanization of Natural Rubber Vulcanizates by Mechanochemical Process

Using a suitable disulfide-based devulcanizing agent, which cleaved the sulfur cross-links in vulcanized rubber at high temperature, devulcanization of gum natural rubber was carried out. High sulfur and medium sulfur, as well as low sulfur–containing rubber vulcanizates were used to study the cleavage of sulfidic bonds. The cure characteristics and mechanical properties of vulcanized natural rubber and revulcanized natural rubber were studied. Thermal properties of the rubber were analyzed by thermogravimetric analysis (TGA), which indicates that the onset degradation temperature further increased on revulcanization with higher amount of disulfide. The properties of the revulcanized natural rubber increased with increasing disulfide concentration, also the mechanical properties of the devulcanized natural rubber were increased by decreasing the sulfur content in the original rubber vulcanizate. From the rheometric study increases in optimum cure time were observed when ground rubber vulcanizates were treated with higher amounts of disulfide. The scanning electronic microscopy (SEM) study suggested the change in failure mechanism as influenced by the type of cross-linking present and the devulcanizing agent used. From infrared (IR) spectroscopy it was observed that the oxidation of the main polymeric chain did not occur at the time of high temperature milling.     

硫化胶粉与脱硫胶粉改性沥青性能研究

对比分析了硫化胶粉和脱硫胶粉微观结构及其改性沥青基本路用性能,研究了硫化胶粉和脱硫胶粉在改性沥青过程中表现出的共性与差异及其原因。结果表明,加入硫化胶粉与脱硫胶粉,均能提高沥青基本路用性能,相同目数下,脱硫胶粉较硫化胶粉交联密度低,表面粗糙,表面极性增加,脱硫胶粉与沥青具有更好的相容性和稳定性,一定掺量下,硫化胶粉能赋予沥青更好的高温稳定性,脱硫胶粉能显著提高沥青低温延度,界面作用及胶粉网络结构的形成对改性沥青路用性能有重大影响。     

Continuous ultrasonic devulcanization of unfilled NR vulcanizates

Sulfur-cured unfilled natural rubber (NR) is successfully devulcanized in a continuous extrusion process under the application of high-power ultrasonic energy. The die characteristics and ultrasonic power consumption are measured. A unique correlation is found between the crosslink density and gel fraction of the devulcanized NR. This correlation is independent of the processing parameters, such as barrel temperature, die gap, flow rate, and amplitude of ultrasound. However, these parameters do influence the degree of devulcanization. In most cases, the degree of devulcanization is found to pass through a maximum at an intermediate level of ultrasonic energy. It is hypothesized that simultaneous breakup and reformation of crosslinks occur during the devulcanization of NR, with the relative contribution of each being determined by the process parameters. The cure curves and mechanical properties of the revulcanized NR are studied. The mechanical properties are found to depend on the revulcanization recipe. On optimizing it, tensile strength as high as 14.2 MPa is achieved, which is about 70% of that of the virgin NR vulcanizate. Ultimate elongation as high as 670% is obtained, which is the same as that of the virgin NR vulcanizate. Such stress–strain behavior is an indication that the devulcanized NR maintains the strain-induced crystallization characteristics inherent to the virgin NR vulcanizates. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 2007–2019, 1998     

Improvement of mechanical properties of rubber compounds using waste rubber/virgin rubber

Ground rubber powder (GRP) and devulcanized rubber waste obtained using the process of continuous shear flow reaction were used as both fillers and a part of rubber in virgin natural rubber (NR). The cure characteristics, swelling behavior, cross‐link density, mechanical properties, and morphology were studied in our laboratory. The GRP and devulcanized rubber, which were generated from passenger car and light truck tires, showed applicable mechanical properties in new rubber compounds, and the compounds that contained devulcanized rubber showed better properties than those with GRP. In particular, devulcanized rubber as a part of rubber obtained through a cross‐link reaction exhibited excellent mechanical properties, with a strong potential for future applications. POLYM. ENG. SCI., 45:1239–1246, 2005. © 2005 Society of Plastics Engineers     

Impact of gamma irradiation on virgin styrene butadiene rubber blended with ultrasonically devulcanized waste rubber

This investigation focused on the opportunity of devulcanizing waste Rubber (WR) by ultrasonication to study the possibility of utilized as an added substance to replace with styrene‐butadiene rubber (SBR) in preparation process with the final aim of preparation new composites. The present work expects to compare the ultrasonic technique and the previous work on devulcanization by mechano‐chemical method. The influence of the ultrasonication treatment on the WR was explored by Fourier transform infrared, thermogravimetric analysis, scanning electron microscopy analysis revealed that ultrasonication was observed to be the best factor impacting the devulcanization procedure, this procedure suggests that use of specific levels of ultrasonic waves to the vulcanized rubber with a specific aim to accomplish a particular breaking of compound connections: scission of C‐S and S‐S bonds without break carbon–carbon (C‐C) bonds. Various blends of devulcanized WR with SBR was treatments with gamma ray then investigated and compared with find out the rubber giving the highest compatibility for compounding and revulcanization. In addition, a comparison of these results was made with the ones of raw SBR rubber compound. POLYM. ENG. SCI., 59:807–813, 2019. © 2019 Society of Plastics Engineers