填充剂表面改性对硫化胶疲劳性能的影响

研究了 13种白炭黑表面改性剂对 NR/BR硫化胶疲劳性能的影响 ,分析了偶联剂改性白炭黑填充硫化胶疲劳过程中微观结构的变化及其对疲劳性能的影响。发现 :不同硅烷类偶联剂对胶料初期性能的影响为 :NDZ2 0 1>NDZ311>NDZ4 0 1>NDZ311W;不同表面活性剂对胶料疲劳性能影响为 ABS>T4 0>ATAC。硫化胶疲劳过程中的“自愈合”能力是影响疲劳性能的重要因素     

复合表面改性剂处理纳米CaCO3粒子填充聚丙烯的结晶形态及力学性能

利用差示扫描量热仪(DSC)和X射线衍射仪(XRD)研究了复合表面改性剂处理纳米C aCO3粒子对聚丙烯结晶形态的影响,并与单一偶联剂表面处理纳米C aCO3粒子进行比较,结果表明,复合表面改性剂处理纳米C aCO3粒子比单一偶联剂表面处理纳米C aCO3粒子有着更强的β晶诱导效应,可使复合材料β晶型的相对含量增加约为20%;而对于熔融温度和结晶度而言,其影响结果基本相同。力学性能研究表明,与单一偶联剂表面处理纳米C aCO3粒子填充聚丙烯相比,复合表面改性剂处理纳米C aCO3粒子填充聚丙烯的力学性能得到进一步改善和提高,尤其是冲击强度和断裂伸长率。     

超细碳酸钙填充型粉末NR的研究

以NR胶乳为原料，超细碳酸钙为填料，高分子树脂为包覆剂兼超细碳酸钙表面改性剂，用凝聚共沉法制备填充型粉末NR。研究了产物粒径及其硫化胶力学性能的影响因素。结果表明，当包覆剂的用量为20质量份时，超细碳酸钙表面改性剂用量为4－5质量份，超细碳酸钙填充量为100－175质量份，可获得粒径≤0.9mm的超细碳酸钙填充型粉末NR达94．5％以上；超细碳酸钙填充量为25－200质量份的范围内，其硫化胶具有优良的力学性能，并显著优于块状NR／超细碳酸钙通过机械混烧所得到的硫化胶，扫描电镜分析显示超细碳酸钙以原生粒子均匀分数于NR基体中，二者形成的界面结合牢固。     

偶联剂Si747原位改性单分散SiO_2/天然橡胶复合材料的结构与性能

采用偶联剂Si747在液相体系中分别对自制单分散白炭黑(SiO_2)和市售沉淀法白炭黑(SiO_2)表面进行改性,利用乳液共混技术制备SiO_2/天然橡胶(NR)复合材料。利用橡胶加工分析仪、DMA、SEM等测试手段对偶联剂Si747改性SiO_2/NR复合材料的结构和性能进行表征。结果表明,在硫化特性方面,与未改性SiO_2相比,偶联剂Si747改性SiO_2/NR复合材料的焦烧时间和工艺正硫化时间均缩短,促进了橡胶的硫化过程,其中改性前后单分散SiO_2/NR硫化胶的焦烧时间和工艺正硫化时间均比沉淀法SiO_2/NR硫化胶长;与未改性单分散SiO_2/NR硫化胶相比,改性单分散SiO_2/NR硫化胶的拉伸强度提高了17.4%,回弹性和耐磨性分别提高了9.5%和32.6%,压缩生热降低了24.3%;与改性沉淀法SiO_2/NR硫化胶相比,改性单分散SiO_2/NR硫化胶的Payne效应最低,填料的分散性更高,填料网络结构更弱;改性单分散SiO_2/NR硫化胶抗湿滑性略低于改性沉淀法SiO_2/NR硫化胶,但滚动阻力更低,更节省能源。     

不同改性剂对纳米SiO2／NR复合材料结构与力学性能的影响

采用硅烷偶联剂（Si-69、KH-590和KH-550）、钛酸酯偶联剂（NGT-201）和十二烷基硫酸钠作为纳米SiO2的表面改性剂，研究了不同改性剂对纳米SiO2／NR复合材料结构与力学性能的影响。结果表明，所采用的改性剂对纳米SiO2／NR复合材料具有较好的改性效果，其增强了纳米SiO2与天然橡胶的界面作用，改善了...     

仿生非光滑表面磨损机理的试验研究

为研究具有不同仿生非光滑表面特征试件的磨损机理,通过加工几种具有非光滑表面形态特征的圆形45#钢试件,利用正交试验方法设计耐磨性试验方案,在国产MM200型摩擦磨损试验机上进行试验.试验结果表明,在相同试验条件下,时间、负荷、速度、形态和分布对耐磨性均有影响,并且耐磨性按照凹坑、凸包、波纹、鳞片形态递减;通过分析磨损后非光滑形态表面的形貌及磨屑的图像,得出非光滑表面形态的磨损机理是磨料磨损,并且其磨损机制是微观切削.     

原位生成纳米SiO2/橡胶复合材料的制备及性能研究

采用原位生成技术制备了纳米SiO2/橡胶复合材料,研究了生胶的结构、反应时间、催化剂、偶联剂种类及用量对SiO2生成量及其增强橡胶硫化胶性能的影响.结果表明:生胶的结构对SiO2的生成量有较大的影响,不同生胶中生成SiO2量的顺序为NR＞IIR＞SBR＞BR＞NBR.随着反应时间的增加,SiO2的生成量增加,72h后基本达到恒定值,偶联剂的种类对SiO2生成量影响不大.当Si-69的用量为2g/100gNR、催化剂为乙二胺、反应时间为72h时,效果最佳.原位生成纳米SiO2填充橡胶硫化胶的性能优于机械共混法填充橡胶硫化胶的性能.     

PVDF/改性BaTiO3复合材料介电性能研究

用硅烷和钛酸酯偶联剂对BaTiO3粉进行了表面处理，使用溶剂法制备了PVDF／BaTiO3复合薄膜，通过疏水亲油实验定性地分析了硅烷和钛酸酯偶联剂对BaTiO3粉的偶联作用可以改善PVDF／BaTiO3的界面结合，通过测定PVDF／BaTiO3的介电常数和介电损耗角正切值表征了复合材料的介电性能，PVDF／BaTiO3扫描电子显微镜（SEM）的微观形态分析发现，经过偶联剂表面处理，BaTiO3粉在PVDF中的分散情况改善，偶联剂的用量对微观形态影响较大。     

磷酸酯偶联剂涂覆对聚乙烯木塑复合材料粘接性能的影响

采用磷酸酯偶联剂对木粉/聚乙烯复合材料进行表面涂覆处理以改善其胶接性能。利用扫描电镜(SEM)、接触角测试、红外光谱(FT-IR)、X射线光电子能谱(XPS)和胶接强度测试研究了磷酸酯偶联剂对聚乙烯木塑复合材料胶接性能的影响。结果表明,经机械打磨并磷酸酯偶联剂涂覆处理后,复合材料的表面粗糙度增加,表面接触角增大。红外分析表明,复合材料表面-OH基团含量减少、C=C基团含量增加,且有C-O-P基团形成。XPS分析表明,复合材料表面引入了P元素,且表面元素的化学环境发生了改变。经机械打磨并磷酸酯偶联剂涂覆处理后,复合材料的表面引入了C=C,从而提高了丙烯酸酯胶粘剂对聚乙烯木塑复合材料的粘接强度。     

硫酸钙晶须的表面改性研究现状

论述了偶联剂、表面活性剂和复合改性剂对硫酸钙晶须表面改性方法及改性机理的研究现状。硫酸钙晶须改性主要是利用改性剂与晶须表面存在的羟基、硫酸钙等发生反应,改变晶须在基体中的分散性、相容性和粘合强度等,从而使晶须达到较好的改性和应用效果。     

Effect of expanded graphite and modified graphite flakes on the physical and thermo-mechanical properties of styrene butadiene rubber/polybutadiene rubber (SBR/BR) blends

The aim of the present research work is to develop expanded graphite (EG) and isocyanate modified graphite nanoplatelets (i-MG) filled SBR/BR blends, which can substitute natural rubber (NR) in some application areas. The present study investigated the effect of i-MG on the physical, mechanical and thermo-mechanical properties of polybutadiene rubber (BR), styrene butadiene rubber (SBR) and SBR/BR blends in the presence of carbon black (CB). Graphite sheets were modified to enhance its dispersion in the rubber matrices, which resulting in an improvement in the overall physical and mechanical properties of the rubber vulcanizates. Compounds based on 50:50 of BR and SBR with ∼3 wt% nanofillers with CB were fabricated by melt mixing. The morphology of the filled rubber blends was investigated by wide angle X-ray diffraction (WAXD) and high resolution transmission electron microscopic (HR-TEM) analyses. The intercalated and delaminated structures of the nanofiller loaded rubber blends were observed. Scanning electron microscopic (SEM) analysis of the cryo-fractured surfaces of the rubber compounds showed more rough and tortuous pathway of the fractured surfaces compared to the fractured surfaces of the only CB loaded rubber composites. Filled rubber compounds exhibit increase in the ΔS (torque difference) value, reduced scorch and cure time compared to their respective controls. Dynamic mechanical thermal analysis (DMTA) of the filled rubber compounds shows an increase in the storage modulus compared to the controls. Isocyanate modified graphite nanoplatelets (i-MG) containing rubber compounds in the presence of CB showed an increase in the mechanical, dynamic mechanical, hardness, abrasion resistance and thermal properties compared to the alone CB filled rubber vulcanizates.     

改性白炭黑/天然橡胶复合材料的制备及性能

采用双-[γ-(三乙氧基硅)丙基]四硫化物(Si69)、γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH570)、乙基三甲氧基硅烷(11-100)对白炭黑进行表面改性,并制备改性白炭黑/天然橡胶复合材料。利用红外光谱(FT-IR)、热重分析(TG)、扫描电镜、橡胶加工分析仪等测试手段对改性白炭黑及改性SiO_2/NR复合材料的结构与性能进行了表征,并研究其硫化性能及力学性能。结果表明,经FT-IR、TG分析,3种硅烷偶联剂已成功接枝到白炭黑表面;改性SiO_2/NR复合材料相对于未改性SiO_2/NR,焦烧时间变长,正硫化时间缩短,结合胶含量增大;改性SiO_2/NR与未改性SiO_2/NR相比其定伸应力、撕裂强度明显提高,但断裂伸长率有所减小;改性白炭黑在天然橡胶基体中的分散性明显提高,其中Si69-SiO_2在天然橡胶基体中的分散性最好;Si69-SiO_2/NR复合材料的滚动阻力与生热最低;改性后的SiO_2/NR复合材料的拉伸断面粗糙程度增加。     

Effects of particle size and structure of carbon blacks on the abrasion of filled elastomer compounds

The effects of the particle size and structure of various carbon blacks on friction and abrasion behavior of filled natural rubber (NR), styrene–butadiene rubber (SBR) and polybutadiene (BR) compounds were investigated using a modified blade abrader. The effect of particle size and structure on abrasion resistance should be considered for the optimum design of desired wear properties. Characteristic parameters were introduced from the particle size and the structure of carbon blacks, with a linear relationship between the Young’s modulus and these characteristic parameters. The frictional coefficient depended not only on the particle size, but also on the structure of carbon black. The rates of abrasion were decreased with increasing surface area and developing structure of carbon blacks. Abrasion rates of the compounds were found to be proportional to a power n of the applied frictional work input. It was also observed that BR compounds caused much slower wear than NR and SBR compounds. The worn surfaces of the rubber compounds filled with carbon black having smaller particle size and a more developed structure showed narrower spaced ridges and better abrasion resistance. It means that smaller particle size and better structure development of carbon black resulted in improved abrasion resistance.     

高密度聚乙烯/顺丁橡胶共混物的耐环境应力开裂性的研究

用定应变方法和定拉力方法研究了高密度聚乙烯(HDPE)及其共混物的耐环境应力开裂性(ESCR)。结果表明,丁基橡胶(IIR)和顺丁橡胶(BR)都可以提高HDPE的ESCR。对HDPE/橡胶二元共混物,BR的效果不如IIR。在改性剂DX-2或DX-3存在下,HDPE/BR共混体系的ESCR有大幅度提高,三元共混物在初始应力强度因子K_0为0.2MPam~1/2时,断裂时间可达到HDPE断裂时间的4倍左右,断面形貌的扫描电镜照片呈网孔状,表明断裂过程具有韧性特点。     

Scanning electron microscopy studies on failure of filled polychloroprene

Scanning electron microscopy (SEM) studies of the effect of particulate fillers (silica and carbon black) and short fibres (silk) on the fracture surface morphology of polychloroprene vulcanizates failed under tension, tear, abrasion and flexing have been made. It has been observed that the type of failure testing and the nature of the filler cause drastic changes in the fractographs. An attempt has been made to correlate these changes with the strength of polychloroprene vulcanizates.     

Novel precipitated silicas: an active filler of synthetic rubber

Highly dispersed silicas have been obtained at a semi-technical scale by precipitation from sodium metasilicate solutions using appropriately diluted solutions of ammonium hydrogencarbonate or ammonium chloride. The difference, as compared to the generally applied technology of silica precipitation using acids or their anhydrides, has been the involvement of the precipitation reaction in alkaline media. Attempts have been made at changing the silica surface character from hydrophilic to more hydrophobic, using a modifier from the group of silane coupling agents. The alkoxysilanes modifiers contained groups with chemical affinity towards functional groups of butadiene–styrene rubber. Modification of silica surface using silane coupling agents has been found to improve the reinforcement of vulcanizates, by increasing the tensile and tear strength in particular.     

白炭黑的功能化改性及其改性橡胶基复合材料的制备与表征

利用沉淀法白炭黑生产工艺,在相同的条件下,选用不同质量分数的羟基羧酸酯作为改性剂进行湿法改性,研究了白炭黑/天然橡胶(NR)复合橡胶的力学性能、动态性能以及动态生热性能。结果表明:制备的白炭黑均为非晶态白炭黑,采用质量分数为6%的羟基羧酸酯改性的白炭黑,其分散性好,颗粒分布均匀,呈近球状,经羟基羧酸酯改性后的白炭黑有效的去除了部分亲水基团,改善了其在NR中的分散性。随着白炭黑用量的增加,分散性变差,损耗因子和动态温升均有所提高,Payne效应增大。当白炭黑用量达到临界值(白炭黑与NR质量比为40∶100)时,白炭黑/NR复合材料表现出较好的性能,改性白炭黑/NR复合材料比未改性白炭黑/NR复合材料的硬度、拉伸强度、断裂伸长率有所提高,而磨耗体积和动态生热则有所下降。动态力学性能测试结果表明,改性白炭黑与天然橡胶的质量比为40∶100时,改性白炭黑/NR复合材料的60℃滚动阻力损耗因子由0.123降到0.104。SEM结果表明,改性白炭黑在橡胶基体中的分散性优于未改性白炭黑,与NR基体界面结合的更加紧密。     

沥青基短切碳纤维表面改性及与纳米填料并用对天然橡胶力学性能的影响

对硝酸(HNO3)改性沥青基短切碳纤维(PCF)及与炭黑(CB)、白炭黑(Silica)协同填充天然橡胶(NR)进行了研究,考察表面改性及并用对PCF表面形貌、石墨化程度和NR力学性能的影响,分析填料与基体的界面相互作用机制。结果表明,HNO3改性后,PCF的表面粗糙度和O/C比显著增加,而石墨化程度有所降低。PCF单独填充NR时不具有增强作用,而与CB或Silica协同填充NR的拉伸强度显著提高,由3MPa分别提高到18.6MPa和23.7MPa;改性后则可达到24.5MPa和24.7MPa。与CB/NR硫化胶相比,PCF-CB/NR硫化胶的拉伸强度略有降低,但改性PCF-CB/NR硫化胶的拉伸强度则提高了25.6%;与Silica/NR硫化胶相比,添加改性前后的碳纤维均使PCF-CB/NR硫化胶的拉伸强度小幅降低。结合不同增强体系的拉伸强度、50%定伸应力和断面形貌SEM照片可以推断出,PCF单独填充NR时,改性前后均与基体的界面粘合较差;对PCF-CB增强体系来说,界面相互作用的提高主要以吸附理论为主,改性后则以机械互锁和吸附理论共同作用为主;对PCF-Silica增强体系,改性前后均以氢键作用为主。     

Microscopic studies on the mechanisms of wear of NR,SBR and HNBR vulcanizates under different conditions

Microscopic investigations, undertaken to understand the mechanism of wear of natural rubber (NR), styrene-butadiene rubber (SBR) and hydrogenated nitrile rubber (HNBR) vulcanizates abraded against hard rock, a knurled aluminium disc and a silicone carbide abrader under different conditions, are reported. The wear of NR and SBR vulcanizates against hard rock at low normal load (6 kPa) takes place by a fatigue wear mechanism and it switches over to frictional wear at high normal load (above 18 kPa). In HNBR vulcanizates the wear takes place by an abrasive wear mechanism. Ridges are observed on worn surface of swollen N R and SBR vulcanizates at low normal load, but at higher normal load the wear takes place by catastrophic fracture and extensive plough marks along the direction of abrasion are observed. The wear of NR and SBR vulcanizates proceeds by frictional wear, even at elevated temperatures. In HNBR vulcanizates, the mechanism changes from abrasive wear at 25C to frictional wear above 50C. Above 50C, ridges are observed and the spacing between adjacent ridges increases with rise of temperature.