亚临界流体挤出法复合诱导丁苯橡胶基轮胎胶粉脱硫及再硫化材料的性能研究

将丁苯橡胶（SBR）基轮胎胶粉（GTR）与三元乙丙橡胶（EPDM）混合物在双螺杆挤出机中熔融挤出,通过亚临界流体与高剪切应力相结合复合诱导SBR基GTR脱硫,研究亚临界流体品种、螺杆转速、促进剂450以及挤出反应温度对脱硫共混物［脱硫GTR（DGTR）/EPDM］凝胶质量分数、门尼粘度、溶胶红外光谱以及SBR/DGTR/EPDM再硫化材料拉伸性能和断面形貌的影响。结果表明：亚临界水、乙醇和丙醇均能很好地促进脱硫反应,提高交联键断裂的选择性,降低DGTR/EPDM的凝胶质量分数和凝胶颗粒尺寸,明显提高SBR/DGTR/EPDM再硫化材料的拉伸性能,其中亚临界乙醇的作用最显著;添加促进剂450能促进脱硫反应;200 ℃时亚临界丙醇脱硫效果较佳。     

亚临界流体挤出法对天然橡胶基轮胎胶粉脱硫化反应的影响

采用亚临界流体挤出法对天然橡胶基轮胎胶粉(GTR)与三元乙丙橡胶(EPDM)进行熔融共混脱硫,得到脱硫轮胎胶粉(DGTR)/EPDM共混物,然后与丁苯橡胶(SBR)共混制备了再硫化材料,考察了亚临界流体品种和双螺杆挤出机螺杆转速、挤出温度对GTR脱硫效果与再硫化材料物理机械性能的影响,并通过傅里叶变换红外光谱和扫描电子显微镜表征了脱硫共混物和再硫化材料。结果表明,在相同挤出温度和螺杆转速条件下,采用亚临界水挤出制得的DGTR/EPDM共混物的凝胶含量和门尼黏度较采用其他亚临界流体挤出共混物低;在3种亚临界醇状态下,采用亚临界甲醇挤出DGTR/EPDM共混物的凝胶含量较低,门尼黏度最高;采用亚临界醇所得DGTR/EPDM/SBR再硫化材料的拉伸性能均明显优于采用亚临界水所得的再硫化材料,其中,采用亚临界乙醇且在挤出温度为180℃、螺杆转速为500 r/min、反应压力为2.0 MPa的条件下,所制得DGTR/EPDM/SBR再硫化材料的拉伸强度和扯断伸长率分别达到19.4 MPa和456%;采用不同亚临界流体脱硫后制得再硫化材料中未熔融凝胶粒子尺寸大小不等,其中采用亚临界水时最小,小于1μm,分别采用亚临界甲醇、乙醇时较小,约为1μm,而采用亚临界丙醇时较大;随着反应温度的升高或螺杆转速的增加,再硫化材料中凝胶粒子的数目及尺寸均明显减小。     

酚硫化物/醇复合促进剂对废轮胎胶应力诱导脱硫反应的影响

在废轮胎胶(GTR)与三元乙丙橡胶(EPDM)熔融挤出过程中添加多烷基苯酚二硫化物(简称420)或/和仲丁醇作为脱硫促进剂,考察了在不同螺杆转速和挤出反应温度下脱硫促进剂对GTR与EPDM脱硫共混物(DGTR/EPDM)凝胶含量和溶胶分子链结构的影响,研究了DGTR/EPDM/丁苯橡胶(SBR)再硫化胶的相态结构及物理...     

亚临界水挤出法复合诱导丁苯橡胶基轮胎胶脱硫化及其对热塑性弹性体性能的影响

在亚临界水挤出反应条件下,研究了双螺杆挤出机的螺杆转速、亚临界水温度、压力及脱硫促进剂种类对丁苯橡胶(SBR)基轮胎脱硫胶(DGTR)/高密度聚乙烯(PE-HD)共混物性能的影响。结果表明,挤出机螺杆的高剪切应力解交联作用与亚临界水分解、降解的解交联作用能产生协同解交联反应,提高脱硫反应效果;正丁胺具有明显促进脱硫反应和保护产物分子双键的功能;在正丁胺作为脱硫促进剂的最佳脱硫反应条件(亚临界水温220℃,螺杆转速1000r/min,水压2.4MPa)下,亚临界水挤出法所得脱硫共混物制备的DGTR/PE-HD/三元乙丙橡胶(EPDM)热塑性弹性体的拉伸强度和断裂伸长率分别达到12.8MPa和614.6%。     

亚临界水挤出法应力诱导挤出条件对废轮胎胶粉脱硫共混物及其热塑性弹性体性能的影响

采用亚临界水挤出法应力诱导废轮胎胶粉解交联反应,研究挤出条件对废轮胎胶粉脱硫共混物[脱硫废轮胎胶粉(DGTR)/高密度聚乙烯(HDPE)共混物]凝胶含量和熔体流动速率以及脱硫共混物/HDPE/三元乙丙橡胶动态硫化热塑性弹性体性能的影响。结果表明:采用亚临界水挤出法应力诱导废轮胎胶粉脱硫,随着螺杆转速增大,挤出反应温度升高和压力增大,脱硫共混物凝胶含量下降和熔体流动速率上升,动态硫化热塑性弹性体拉伸强度提高;在正丁胺作脱硫促进剂、挤出反应温度为220℃、挤出反应压力为2.4 MPa、螺杆转速为1 000 r·min~(-1)的优化条件下,亚临界水挤出法制得的脱硫共混物/HDPE/EPDM热塑性弹性体的拉伸强度和拉断伸长率分别达到12.8 MPa和615%。     

废旧轮胎胶粉应力诱导脱硫反应影响因素的研究

在废旧轮胎胶粉/EPDM的熔融挤出过程中,以仲丁醇为脱硫反应促进剂,研究螺杆转速和挤出反应温度对脱硫共混物凝胶质量分数(w)、凝胶分子链结构以及SBR/脱硫共混物再硫化材料物理性能的影响。结果表明:在废旧轮胎胶粉/EPDM的熔融挤出过程中,随着螺杆转速和挤出反应温度的升高,废旧轮胎胶粉颗粒所受的机械剪切应力作用增强,引起废旧轮胎胶粉中交联网络的断裂、降解或解交联反应,导致脱硫共混物w显著减小以及SBR/脱硫共混物再硫化材料中凝胶粒子尺寸明显减小;添加仲丁醇有利于脱硫反应的进行,并具有抑制交联副反应和保护脱硫产物中双键的作用,使脱硫共混物的w进一步减小;在螺杆转速为1 000 r.min-1、挤出反应温度为240℃的条件下,SBR/脱硫共混物(添加仲丁醇)再硫化材料的拉伸强度和拉断伸长率分别为19.3 MPa和567%。     

轮胎胶应力诱导脱硫及产物结构与性能

在轮胎胶粉（GTR）与三元乙丙橡胶（EPDM）的共混物熔融挤出过程中添加二硫化四甲基秋兰母（TMTD）和过氧化二异丙苯（DCP）作为脱硫反应促进剂,考察双螺杆挤出机的螺杆转速和挤出温度对再生胶（DGTR-EP-DM）的凝胶含量、溶胶分子链结构及再硫化材料力学性能的影响.结果表明：加入TMTD有助于反应体系中自由基的链转移反应,有助于对脱硫产物中较活泼双键的保护作用.当同时加入TMTD和DCP作为脱硫反应促进剂进行反应时,两者的协同作用有助于降解反应的进行,导致DGTR-EPDM中凝胶粒子尺寸的明显减小,并且其与丁苯橡胶（SBR）共混硫化胶力学性能的明显增加.在240℃和1 000 r/min的条件下,添加TMTD-DCP时,所得DGTR-EP-DM-SBR硫化胶的拉伸强度和断裂伸长率可分别达到19.2 MPa和554%.     

轮胎胶应力诱导脱硫化及PE-HD动态交联热塑性弹性体制备

采用在废旧轮胎胶粉(GTR)与高密度聚乙烯(PE-HD)的熔融挤出过程中提高双螺杆挤出机螺杆转速的高剪切应力诱导方法,研究了双螺杆挤出机的螺杆转速、挤出反应温度及脱硫促进剂仲丁醇、烷基酚多硫化物(420或450)和正丁胺对轮胎胶脱硫共混物的凝胶含量、熔体流动速率、溶胶红外吸收光谱及轮胎胶脱硫共混物/三元乙丙橡胶(EPDM)动态交联热塑性弹性体力学性能的影响。结果表明:高转速同向双螺杆挤出机的高剪切作用可诱发废旧轮胎胶共混物中交联网络的断链和解交联反应,引起脱硫共混物凝胶含量的下降、未熔融凝胶颗粒尺寸的减小及熔体流动速率的增加;4种促进剂均具有明显促进脱硫反应的作用,其中450或正丁胺的促进脱硫效果较好,并引起脱硫共混物凝胶含量下降、熔体流动速率上升及动态交联热塑性弹性体力学性能的明显改善;当以正丁胺为脱硫促进剂时,最佳脱硫反应条件(240℃和1000r/min)下,脱硫共混物/EPDM动态交联热塑性弹性体的拉伸强度和断裂伸长率分别达到12.5MPa和440.6%。     

轮胎胶脱硫共混物增韧聚丙烯的影响因素

在轮胎胶粉与热塑性弹性体(POE)共混物的熔融挤出过程中添加有机醇类化合物作为脱硫反应促进剂,研究双螺杆挤出机的螺杆转速和挤出反应温度对轮胎胶脱硫共混物的凝胶含量、溶胶分子链结构及增韧PP材料力学性能的影响.实验结果表明:随着双螺杆挤出机螺杆转速的增加或挤出反应温度的升高,轮胎胶粉颗粒所受到的机械剪切应力作用或热能作用均明显增强,强烈的剪切应力和热能可引发轮胎胶中交联网络的断裂、降解或解交联反应发生,引起脱硫共混物中凝胶含量明显下降、凝胶粒子尺寸明显减小以及与PP材料相容性明显改善.添加有机醇-1化合物作为脱硫反应促进剂时,有利于脱硫反应的进行,有利于脱硫产物中双键的保护,并引起脱硫共混物凝胶合量进一步下降、凝胶颗粒尺寸进一步减小和增韧PP材料力学性能进一步提高.在240℃条件下添加有机醇-1化舍物进行脱硫反应,当脱硫反应螺杆转速由400 r/min增加至1200 r/min时,所得脱硫共混物增韧PP材料(PP/DGTR/POE=70/24/6)的缺口冲击强度可由17.4kJ/m2提高至34.4 kJ/m2,并且引起此共混材料拉伸强度、断裂伸长率、弯曲模量及熔体指数的明显增大.     

单螺杆挤出机连续脱硫制备再生胶的结构与性能

利用本课题组研制的单螺杆挤出机,对废旧轮胎胶(GTR)粉进行连续脱硫制备再生胶(DGTR),并对DGTR进行再硫化制成DGTR硫化试样.结果显示,随螺杆转速增加,DGTR凝胶含量和DGTR硫化试样交联密度逐渐降低,DGTR硫化试样的拉伸强度和拉断伸长率有所提高;螺杆转速设定为40 r·min^-1时,在205℃脱硫温度下取得了最好的脱硫效果,DGTR硫化试样的拉伸强度和拉断伸长率分别约为11 MPa和386%.从红外光谱和光电子能谱的分析结果推测,在单螺杆挤出机的剪切和热等的共同作用下,GTR粉中部分S-S键和C-S键发生了断裂.     

Effects of shear stress and subcritical water on devulcanization of styrene–butadiene rubber based ground tire rubber in a twin‐screw extruder

The devulcanization reaction of styrene–butadiene rubber (SBR) based ground tire rubber (GTR) in GTR/ethylene–propylene–diene monomer rubber (EPDM) blend was investigated through a compound‐induced reaction by increasing screw rotation speed and being in the presence of subcritical water. The effects of temperature, pressure, screw rotation speed, or promoting agents on the gel content, Mooney viscosity, and Fourier transform infrared spectra of the sol of the devulcanized blends (devulcanized ground tire rubber (DGTR)/EPDM) were measured, and the mechanical properties and microstructures of the revulcanized blend ((DGTR/EPDM)/SBR) were characterized. The results show that subcritical water as a swelling agent and reaction medium promotes the devulcanization reaction, increases the selectivity of the crosslink breakage, keeps the extrusion material from oxidative degradation, reduces the gel particle size of the devulcanized blends, and significantly improves the mechanical properties of the revulcanized SBR/(DGTR/EPDM) blends. In subcritical water, the suitable promoting agents (alkylphenol polysulfide 450, hydrogen peroxide H₂O₂, or 450/H₂O₂) accelerate the devulcanization reaction, keep the double bond content, and lead to further decrease of the gel content and Mooney viscosity of the devulcanized blends and further increase of the mechanical properties of the revulcanized SBR/(DGTR/EPDM) blends. Especially the compound promoting agent (450/H₂O₂) improves the selectivity of the crosslink breakage in devulcanization of SBR‐based GTR. When 450/H₂O₂ is added as a compound promoting agent at the best reaction condition in subcritical water (200°C, 1.6 MPa and 1000 rpm), the tensile strength and elongation at break of the revulcanized SBR/(DGTR/EPDM) blends reach to 85.4% and 201% of vulcanized SBR (24.0 MPa, 356%), respectively. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1845–1854, 2013     

氧化亚铁硫杆菌脱硫胎面胶粉/丁苯橡胶并用胶的性能研究

采用氧化亚铁硫杆菌对胎面胶粉(GTR)进行脱硫再生,将生物脱硫胎面胶粉(DGTR)与丁苯橡胶(SBR)共混制备DGTR/SBR并用胶,并对其性能进行研究。结果表明:从氧化亚铁硫杆菌与GTR共培养脱硫再生过程发现,氧化亚铁硫杆菌可以代谢硫化胶粉中的化合硫,脱硫后胶粉的溶胶质量分数增大;与GTR/SBR并用胶相比,DGTR/SBR并用胶的交联密度较小,物理性能显著提高;DGTR/SBR并用胶分子间的摩擦阻力减小,玻璃化温度降低;与GTR相比,DGTR与SBR的界面结合更好。     

Balancing mechanical properties and processability for devulcanized ground tire rubber using industrially sized single‐screw extruder

Devulcanized ground tire rubber (DGTR) samples were produced using an independently developed industrially sized single‐screw extruder. The DGTR was further revulcanized to produce revulcanized DGTR (RDGTR) samples. The structure and properties of the produced samples were investigated via tests and characterization of sol fraction, crosslink density, Fourier transform infrared spectroscopy spectra, X‐ray photoelectron spectroscopy spectra, Mooney viscosity, curing characteristics, dynamic rheology, tensile properties, and surface morphology. The results demonstrate that the extruder can effectively break up crosslinked structure of ground tire rubber to achieve high devulcanization level (characterized by sol fraction and crosslink density), which is mainly associated with its moderate shear strength. The balance between mechanical properties and processability for the DGTR samples was analyzed. Lower ratios of main‐chain to crosslink scission and good processability (mainly characterized by modest Mooney viscosity) for the DGTR samples, and high tensile strengths and elongations at break for the RDGTR samples are obtained via appropriately combining the barrel temperature and screw speed. High quality DGTR sample with tensile strength and elongations at break of up to 11 MPa and 370%, respectively, is prepared under the conditions used in this work. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43761.     

Continuous ultrasonic devulcanization of NR/SBR blends

The ultrasonic devulcanization of sulfur‐cured natural rubber (NR)/styrene–butadiene rubber (SBR) blends was studied with the goal of understanding the devulcanization of rubber vulcanizates in which two networks of different natures were present. Also, similarities and differences in the devulcanization behaviors of NR, SBR, and their blends were found. During the devulcanization of cured NR/SBR blends, we observed that, as for NR, the ultrasonic power consumption for 75/25 and 50/50 (w/w) NR/SBR blends passed through a maximum at 7.5 μm. For SBR and 25/75 (w/w) NR/SBR blends, the power consumption increased with increasing ultrasonic amplitude. The higher power consumption led to a higher degree of devulcanization. The crosslink densities of the devulcanized 25/75, 50/50, and 75/25 (w/w) NR/SBR blends were lower than those of the devulcanized NR and SBR, possibly because of the reduced degree of unsaturation. The tensile properties of the revulcanized blends were lower than those of the virgin vulcanized blends. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 160–168, 2002     

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.     

Comparative analysis of ultrasonically devulcanized unfilled SBR,NR, and EPDM rubbers

The comparative study of the continuous ultrasonic devulcanization of various unfilled rubbers [natural rubber, styrene–butadiene rubber (SBR), ethylene–propylene–diene rubber (EPDM)] is carried out by means of a ultrasonic reactor. The power consumption, gel fraction, crosslink density, cure behavior, and physical properties of devulcanized rubbers were measured. The glass transition temperatures of virgin, vulcanized, and devulcanized rubbers were determined in order to characterize the difference in the mobility of rubber molecules for each rubber before and after devulcanization. Thermogravimetric analysis was also used to determine thermal stability of the various rubbers. A unique correlation between gel fraction and crosslink density indicated significant differences in the efficiency of devulcanization of various rubbers. Under certain devulcanization conditions, the mechanical properties of revulcanized SBR and EPDM rubbers were found to improve compared to those of the original rubbers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 434–441, 2003