高耐磨炭黑填充型粉末NR研究(Ⅲ)硫化胶的物理机械性能

研究了高耐磨炭黑(N330)填充型粉末天然橡胶[P(NR/N330)]硫化胶的物理机械性能.结果发现炭黑乳化剂、炭黑、操作油和包覆剂的用量及玻璃化转变温度对P(NR/N330)硫化胶的物理机械性能的影响比较明显.在适宜的粉末化条件下制备的P(NR/N330),其硫化胶的物理机械性能优于天然胶乳与炭黑的简单共沉胶(ENR/N330),而300%定伸应力则低于块状NR/N330机械混炼胶(MNR/N330).P(NR/N330)硫化胶拉伸断面形貌的SEM分析表明,包覆剂在用量为15份时,与NR基体形成互锁结构;DSC分析表明,二者部分相容,因此硫化胶具有较好的物理机械性能.     

稀土掺杂高耐磨炭黑填充型粉末NR研究I.硫化胶的物理机械性能

以天然胶(NR)乳为原料,稀土化合物改性高耐磨炭黑N330(N330-Re)为填充隔离剂,用凝聚共沉法制备了稀土掺杂高耐磨炭黑填充型粉末NR[P(NR/N330-Re)],研究了炭黑乳化剂用量、粉末化温度、硫磺用量、稀土元素的种类及用量、过渡金属Zn的用量、N330-Re的用量等因素对其硫化胶物理机械性能的影响.结果表明,所选用的稀土化合物对高耐磨炭黑N330具有优良的改性效果,从而对P(NR/N330-Re)硫化胶有显著的补强作用,其中以Sm2O3与La2O3改性效果最佳.     

稀土掺杂炭黑填充型非硫调节型粉末氯丁橡胶的性能与结构

利用镧系稀土（Ln）对炭黑表面有特殊的活化作用,采用化学沉积法制备了稀土掺杂炭黑（HAF—Ln）,并将HAF—Ln与非硫调节型氯丁胶乳（CR232胶乳）进行共混,采用凝聚共沉法制备了稀土掺杂炭黑填充型非硫调节型粉末氟丁橡胶[P（CR232／HAF—Ln）]。研究了稀土类型及用量对P（CR232／HAF—Ln）硫化胶力学性能的影响,发现采用稀土La、Sm和Tm掺杂的P（CR232／HAF—Ln）具有较好的力学性能。通过P（CR232／HAF—Ln）硫化胶拉伸断面的SEM分析,发现稀土La、Sm和Tm可有效改善炭黑在橡胶基体中的分散。     

稀土掺杂高耐磨炭黑填充型粉末NR研究(Ⅱ)交联密度

以溶胀指数SI（Swelling Index）为指示参数，研究了稀土用量及炭黑用量对稀土掺杂高耐磨炭黑填充型粉末天然橡胶[P（NR／N330-Ln）]硫化胶的交联密度的影响，并与无稀土粉末胶[P（NR／N330）]及无稀土块胶（MNR／N330）的硫化胶做对比。结果表明，随着稀土用量的增加，硫化胶的溶胀指数（SI）的变化出现4个阶段，这是N330粒子上的稀土对硫化胶表现交联密度的贡献有两种相反的作用，即阻碍生成炭黑凝胶从而降低表现交联密度的作用，增大N330-Ln的表面效应，提高稀土结合橡胶的生成量从而提高表现交联密度的作用的综合结果。随着炭黑用量的增加，P（NR／N330）和P（NR／N330-Sm）硫化胶的交联密度高于MNR／N330硫化胶，各种硫化胶在炭黑填充量为100份时的交联密度几乎相同。     

SBR/高耐磨炭黑的共混方式对其硫化胶性能的影响

测定了高耐磨炭黑填充型粉末SBR[P(SBR/HAF)],SBR胶乳/炭黑共沉胶(ESBR/HAF)和SBR块胶/炭黑机械混炼胶(MSBR/HAF)3种不同共混方式的硫化胶的力学性能.结果发现,在炭黑填充量相同的条件下,3种硫化胶的定伸应力和拉伸强度的大小顺序为MSBR/HAF＞P(SBR/HAF)＞ESBR/HAF,撕裂强度及扯断永久变形的大小顺序为ESBR/HAF＞P(SBR/HAF)＞MSBR/HAF.拉伸断面形貌的SEM分析表明,MS-BR/HAF硫化胶以微裂纹导致基体空化,P(SBR/HAF)以既有微裂纹导致基体空化又有裂缝扩展及分支,ES-BR/HAF则以裂缝扩展及分支的方式断裂.     

稀土掺杂高耐磨炭黑填充型粉末NR研究——Ⅰ．硫化胶的物理机械性能

以天然胶(NR)乳为原料，稀土化合物改性高耐磨炭黑N330(N330-Re)为填充隔离剂，用凝聚共沉法制备了稀土掺杂高耐磨炭黑填充型粉末NR[P(NR／N330-Re)]，研究了炭黑乳化剂用量、粉末化温度、硫磺用量、稀土元素的种类及用量、过渡金属Zn的用量、N330-Re的用量等因素对其硫化胶物理机械性能的影响。结果表明，所选用的稀土化合物对高耐磨炭黑N330具有优良的改性效果，从而对P(NR／N330-Re)硫化胶有显著的补强作用，其中以Sm2O3与La2O3改性效果最佳。     

硫化促进剂O,O′-二辛基二硫代磷酸镨在天然橡胶中的应用

将自制不含氮元素、硫化过程中不会产生亚硝胺的O,O′-二辛基二硫代磷酸镨(PrDTP-8)用作天然橡胶(NR)的硫化促进剂。结果表明,PrDTP-8对NR具有明显的硫化促进效果;PrDTP-8用量为3.36份,硫化胶的力学性能最佳,即硬度、拉伸强度、撕裂强度、100%定伸应力和300%定伸应力均最大,而拉断伸长率最小。硫化动力学研究表明,含PrDTP-8的混炼胶硫化反应活化能E和频率因子A分别为87.15kJ/mol和2.33E 10。     

交联密度对白炭黑/炭黑复合补强NR胎面胶性能的影响

针对卡车胎胎面胶配方,研究了交联密度对白炭黑/炭黑复合填充天然橡胶(NR)胎面胶性能的影响。结果表明,随着促进剂NS、S用量的增加,白炭黑/炭黑复合填充NR混炼胶的硫化速度逐渐加快,焦烧时间ts1、正硫化时间tc90逐渐缩短,硫化胶交联密度明显逐渐提高,导致NR硫化胶300%定伸应力提高,断裂伸长率下降。随着交联密度的提高,DIN及Akron磨耗体积逐渐减小,耐磨性明显提高;NR硫化胶剪切储能模量G′逐渐提高,损耗模量G″的频率依赖性逐渐下降,且二者都随剪切频率增加而提高。损耗因子tanδ在频率扫描及温度扫描下随交联密度增加而减小,与压缩生热结果相一致。     

稀土镝掺杂炭黑填充型粉末NR的挤出特性研究

采用液相化学沉积法和凝聚共沉法制备稀土镝掺杂炭黑填充型粉末NR[P(NR/HAF-Dy)],研究其毛细管挤出流变行为和复杂口型挤出特性,并与传统的炭黑填充型粉末NR[P(NR/HAF)]和NR/炭黑干法混炼胶(NR/HAF)进行比较.结果表明,在温度为90～150 ℃及剪切速率为20～1 500 s-1的范围内,3种混炼胶的表观剪切粘度由小到大的顺序为P(NR/HAF-Dy),P(NR/HAF),NR/HAF;当Dy/HAF用量比为4/100时,P(NR/HAF-Dy)混炼胶具有较低的表观剪切粘度和稳定的非牛顿流体特性;与NR/HAF相比,P(NR/HAF)混炼胶具有较好的复杂口型挤出加工性能,P(NR/HAF-Dy)混炼胶的挤出性能则更为优良.     

顺丁橡胶和白炭黑对炭黑/天然橡胶复合材料性能的影响

试验研究顺丁橡胶(BR)和白炭黑对炭黑/天然橡胶(NR)复合材料性能的影响。结果表明:与炭黑/NR复合材料相比,炭黑/NR/BR胶料的焦烧时间略有缩短,交联程度增大,硫化胶的300%定伸应力增大,压缩生热降低,抗切割性能下降,耐磨性能提高,滚动阻力减小;炭黑/白炭黑/NR胶料的交联程度减小,硫化胶的拉断伸长率和撕裂强度明显增大,压缩生热略有升高,抗切割性能和耐磨性能提高,滚动阻力增大(须通过加入偶联剂予以改善)。     

Mechanical properties and crosslink density of rare earth‐modified high‐abrasion furnace‐filled powdered natural rubber

High‐abrasion furnace‐filled powdered natural rubber [P(NR/HAF)] has more advantages than traditional HAF‐filled bale NR (NR/HAF) because of its better environmental performance and easier processing quality, but its lower mechanical properties are disadvantageous. To improve the mechanical properties, rare earth‐modified HAF‐filled powdered NR [P(NR/HAF‐Ln)] (Ln = Sm,La,Pr) was prepared by means of coacervation–coprecipitation, using rare earth‐modified HAF as separant and filler. The effect on mechanical properties of P(NR/HAF‐Ln) vulcanizate exerted by the emulsifier/HAF ratio, powdering temperature, Ln/HAF ratio and type of Ln, and HAF content were studied. The results indicated that when optimum formulation, the mechanical properties of P(NR/HAF‐Ln) vulcanizate were better than P(NR/HAF) vulcanizate. In addition, the relationship of the apparent crosslink density and HAF content of P(NR/HAF‐Ln), P(NR/HAF), NR/HAF vulcanizates was also investigated, along with their SEM microphotographs of tensile fracture surface, which indicated that the excellent mechanical properties of P(NR/HAF‐Ln) vulcanizate was attributed to correct amount of Ln that could increase crosslink density and reinforce the interface structure of NR matrix/HAF‐Ln particle. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1755–1762, 2006     

Rare earth compounds modified carbon black filled powdered natural rubber: Preparation,morphology and properties

Ten types of rare earth (RE) compounds modified carbon black (HAF‐RE) were prepared using chemical‐deposit method, then HAF‐RE were mixed with natural rubber latex to prepare HAF‐RE filled powdered natural rubber [P(NR/HAF‐RE)] by a carbon black/rubber latex coagulation method. It is found that most of the P(NR/HAF‐RE) vulcanizates showed better mechanical properties, especially higher tensile modulus, and tensile strength, compared with none‐rare earth modified carbon black filled powdered natural rubber [P(NR/HAF)]. Dysprosium (Dy) modified carbon black (HAF‐Dy) filled powdered natural rubber [P(NR/HAF‐Dy)] was chosen for intensive investigation because of its better comprehensive mechanical properties. It is found that the adding of Dy compounds could help to get smaller particles with narrower particle size distribution, and results from the SEM analysis show that carbon black has been dispersed in rubber matrix uniformly with diameter of 50–150 nm. The TEM analysis showed that Dy compounds could obviously reduce the aggregation of primary particles of carbon black, and promote the dispersion of carbon black in P(NR/HAF‐Dy) particles. © 2008 Wiley Periodicals, Inc. JAppl Polym Sci 2008     

Carbon black filled powdered natural rubber: Preparation,particle size distribution,mechanical properties,and structures

Carbon black (HAF) filled powdered natural rubber (P(NR/HAF)) was prepared and the particle size distribution, mechanical properties, and micromorphology of P(NR/HAF) were studied. A carbon black–rubber latex coagulation method was developed for preparing carbon black filled free‐flowing, noncontact staining NR powders with particle diameter less than 0.9 mm. A powdering mechanism model was put forward to describe the powdering process, which shows that the key technical points consist in the surfactant with good emulsification properties and the polymer coating resin with good film forming properties. SEM analysis shows that carbon black and rubber matrix have formed a macroscopic homogenization in the P(NR/HAF) particles without contact staining, and carbon black particles are well dispersed in rubber matrix with diameter of about 50–150 nm. P(NR/HAF) vulcanizate showed better mechanical properties than bale natural rubber/carbon black blends (NR/HAF) and simple NR latex/carbon black blends (NRL/HAF), which depends primarily upon the absence of free carbon black, the fine dispersion of filler on the rubber matrix, and the better interaction between carbon black and rubber matrix due to the proper preparation condition of noncontact staining carbon black filled powdered NR. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1763–1774, 2006     

Particle size distribution,mixing behavior,and mechanical properties of carbon black (high‐abrasion furnace)–filled powdered styrene butadiene rubber

High‐abrasion furnace black (HAF, grade N330)–filled powdered styrene butadiene rubber [P(SBR/HAF)] was prepared and the particle size distribution, mixing behavior in a laboratory mixer, and mechanical properties of P(SBR/HAF) were studied. A carbon black–rubber latex coagulation method was developed for preparing carbon black–filled free‐flowing, noncontact staining SBR powders, with particle diameter less than 0.9 mm, under the following conditions: carbon black content > 40 phr, emulsifier/carbon black ratio > 0.02, and coating resin content > 2.5 phr. Over the experimental range, the mixing torque τ_α of P(SBR/HAF) was not as sensitive to carbon black content and mixing temperature as that of HAF‐filled bale SBR (SBR/HAF), whereas the temperature build‐up ΔT showed little dependency on carbon black content. Compared with SBR/HAF, P(SBR/HAF) showed a 20–30% mixing energy reduction with high carbon black content (>30 phr), which confers to powdered SBR good prospects for internal mixing. Carbon black and the rubber matrix formed a macroscopic homogenization in P(SBR/HAF), and the incorporation step is not obvious in the internal mixing processing results in these special mixing behaviors of P(SBR/HAF). A novel mixing model of carbon black–filled powdered rubber, during the mixing process in an internal mixer, was proposed based on the special mixing behaviors. P(SBR/HAF) vulcanizate showed better mechanical properties than those of SBR/HAF, dependent primarily on the absence of free carbon black and a fine dispersion of filler on the rubber matrix attributed to the proper preparation conditions of noncontact staining carbon black–filled powdered SBR. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2494–2508, 2004     

三种微生物脱硫废乳胶及其填充天然橡胶的力学性能比较

利用三种微生物鞘氨醇单胞菌、脂环酸芽孢杆菌和酵母菌对废乳胶(WLR)进行了脱硫再生,考察了脱硫过程中微生物的生长情况以及脱硫前后WLR溶胀和交联密度的变化,并将WLR和脱硫WLR(DWLR)以不同份数填充到天然橡胶(NR)中,对比了DWLR/NR硫化胶和WLR/NR硫化胶的力学性能和交联密度。结果表明,利用鞘氨醇单胞菌脱硫的WLR溶胀值较高,交联密度较低。随着乳胶用量的增加,填充NR硫化胶的拉伸强度和交联密度逐渐降低,扯断生长率逐渐增加。DWLR/NR硫化胶的力学性能明显优于WLR/NR硫化胶,且鞘氨醇单胞菌脱硫的DWLR/NR的力学性能明显优于其它两种微生物脱硫的DWLR/NR硫化胶。     

用作载重子午线轮胎胎面胶的炭黑填充粉末NR结构与性能研究

以天然胶乳和炭黑N234为原料,采用凝聚共沉法制备炭黑填充型粉末NR[P(NR/CB)],研究炭黑用量和不同配方对胶料硫化特性、物理性能、交联密度、微观结构、Payne效应及动态力学性能的影响,并与采用传统机械混炼法制备的炭黑/NR(CB/NR)进行对比.结果表明,与CB/NR硫化胶相比,P(NR/CB)硫化胶具有较高的拉伸强度、撕裂强度、回弹值和抗湿滑性能以及较低的滚动阻力,耐屈挠性能和耐磨性能大致相当,而动态压缩生热和压缩永久变形则降低了近50%.     

The mastication characteristics of powdered carbon black filled natural rubber during internal mixing

Powdered carbon black filled natural rubber, P(NR/HAF), is a premixture of natural rubber and carbon black in powdered form with good carbon black dispersion throughout the rubber matrix. In this study, the mastication properties of P(NR/HAF) were observed under a wide temperature range (50–110°C) and rotor speed (30–100 rpm) range, using a mixing head attached to Brabender Plasticorder. It was found that P(NR/HAF) showed different mastication characteristic, compared to the traditional internal mastication theories of natural rubber; poor masticating properties of P(NR/HAF) are observed with low rotor speed and high temperature and a ‘‘stable zone’’ with middle rotor speed and lower temperature. The Mooney viscosity of rubber batch under different rotor speed and temperature was almost the same, and mastication properties were unsatisfactory. It was considered that the higher temperature build‐up of the mixing batch of P(NR/HAF) during the early stage of internal mixing results in the special mastication properties. A quadratic mastication model of P(NR/HAF), based on the multivariate regression analysis and stepwise regression analysis, was used to predict the mastication characters of P(NR/HAF) in internal mixer under varied temperature and rotor speed. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers