漂珠改性天然橡胶复合材料的性能研究

利用Si-6偶联剂改性漂珠,通过直接共混法将改性的漂珠和NR制备漂珠/NR复合材料.研究复合材料的拉伸性能、硬度、热性能变化规律,并利用SEM研究试样拉伸断裂机理.结果表明:改性后漂珠的粒径减小,呈不规则的块状结构.与半补强炭黑/NR相比,漂珠/NR复合材料的断裂伸长率提高,拉伸强度未见变小,硬度减小.价格低廉的漂珠能替代炭黑作橡胶补强材料.     

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。     

纳米介孔MCM-41-M/偶联剂体系对天然橡胶性能的影响

制备了天然橡胶(NR)/MCM-41-M、NR/偶联剂化学改性纳米介孔MCM-41-M、NR/MCM-41-M/偶联剂复合材料,研究了不同含量的MCM-41-M、不同种类偶联剂对MCM 41-M的改性以及偶联剂的添加方式对NR复合材料性能的影响.结果表明;MCM-41-M在NR中有明显的补强作用,当代替3份炭黑时NR基复合材料的拉伸强度达到最大值,比纯NR提高了12.7%。与MCM-41-M和KH-570直接添加到NR中相比,MCM-41-M经偶联剂KH-570改性使拉伸强度提高了50%。将MCM-41-M用偶联剂KH 570改性后添加到NR中,使NR的玻璃化转变温度升高、玻璃化转变区的损耗角减小、储能模量提高到最大。     

天然橡胶-氢化丁腈橡胶的共硫化及性能研究

天然橡胶(NR)和氢化丁腈橡胶(HNBR)因不饱和度和极性的差异,存在硫化速度不匹配、填料分散等问题,难以实现两胶的并用。本文通过先制备不同硫黄/促进剂比例的NR和HNBR母炼胶,再将母炼胶并用制备NR/HNBR复合材料,解决了NR和HNBR共硫化的问题。研究了NR/HNBR的相态结构和填料在NR和HNBR两相的分散状态,结合相态结构和填料分散分析了NR/HNBR并用比对复合材料硫化特性、动静态力学性能、耐磨性和压缩温升的影响。结果表明:并用HNBR的复合材料混炼胶的门尼黏度增大,焦烧时间和正硫化时间缩短;随着HNBR含量增加,HNBR相的尺寸增大,硫化胶的硬度及100%和300%定伸应力增加,拉伸强度、撕裂强度、断裂伸长率和拉断永久变形减小,耐磨性和抗湿滑性提高,压缩疲劳温升增大。     

尼龙短纤维增强天然橡胶复合材料的性能研究

采用液体橡胶对尼龙纤维进行改性,再用超声对纤维进行处理,将处理后的尼龙短纤维(NSF)和天然橡胶(NR)制成母炼胶,再制得NSF/NR硫化胶复合材料。考察了液体橡胶、超声处理对纤维的改性效果及对NSF/NR硫化胶复合材料的力学性能的影响。实验结果表明:采用端羟基聚丁二烯(CTPB)浸渍,并超声处理7h,纤维与橡胶界面得到改善,提高了相容性,力学性能进一步提高,制得的NSF/NR硫化胶复合材料与未经改性处理的硫化胶复合材料相比,拉伸强度达到24.87MPa,提高了21.67%;断裂伸长率达到1061.190%,提高了17.16%;100%定伸应力达到3.944MPa,提高了30.38%;300%定伸应力达到7.138MPa,提高了13.66%;撕裂强度达到60.830kN/m,提高了5.41%。     

叶蜡石基改性复合粉体部分替代N330对SBR/N330纳米复合材料性能的影响

利用工业化生产中通用的橡胶混炼工艺制备了丁苯橡胶(SBR)/N330/叶蜡石基改性复合纳米粉体(PBMCN)纳米复合材料.对改性的叶蜡石基复合纳米粉体在SBR/N330/PBMCN纳米复合材料中的分散性能及对SBR/N330/PBMCN体系纳米复合材料的力学和硫化性能的影响进行了研究.结果表明,PBMCN在SBR/N330/PBMCN复合材料中的分散效果良好.PBMCN取代N330 20%(质量分数)时,SBR/N330/PBMCN复合材料的拉伸强度、拉断伸长率及硫化性能都得到了改善.分析讨论了PBMCN在SBR/N330/PBMCN复合材料中的补强机理.     

改性白炭黑在天然橡胶中的分散性及防老作用EI北大核心CSCD

采用γ-氨丙基三乙氧基硅烷(KH550)与3,5-二叔丁基-4-羟基苯乙酸为改性剂,通过两步法改性白炭黑(SiO_2),制备得到一种具有防老功能的白炭黑,将防老白炭黑添加到天然橡胶(NR)中,制备防老SiO_2/NR复合材料,并与未改性SiO_2/NR复合材料进行对比。结果表明,防老SiO_2/NR的焦烧时间变化不大,正硫化时间缩短了35.43%;橡胶加工分析仪与扫描电镜测试结果显示,白炭黑经过接枝改性后在天然橡胶中的分散性得到改善。在100℃下,随着老化时间的不同,防老SiO_2/NR的断裂伸长率变化率与拉伸强度变化率降幅小于未改性SiO_2/NR复合材料。最后,采用FlynnWall-Ozawa法考察了防老SiO_2/NR硫化胶的热氧化活化能,发现白炭黑接枝了防老剂后,SiO_2/NR的热氧化活化能有所提高,起始热失重温度提高了13.4℃。     

改性白炭黑在天然橡胶中的分散性及防老作用

采用γ-氨丙基三乙氧基硅烷(KH550)与3,5-二叔丁基-4-羟基苯乙酸为改性剂,通过两步法改性白炭黑(SiO_2),制备得到一种具有防老功能的白炭黑,将防老白炭黑添加到天然橡胶(NR)中,制备防老SiO_2/NR复合材料,并与未改性SiO_2/NR复合材料进行对比。结果表明,防老SiO_2/NR的焦烧时间变化不大,正硫化时间缩短了35.43%;橡胶加工分析仪与扫描电镜测试结果显示,白炭黑经过接枝改性后在天然橡胶中的分散性得到改善。在100℃下,随着老化时间的不同,防老SiO_2/NR的断裂伸长率变化率与拉伸强度变化率降幅小于未改性SiO_2/NR复合材料。最后,采用FlynnWall-Ozawa法考察了防老SiO_2/NR硫化胶的热氧化活化能,发现白炭黑接枝了防老剂后,SiO_2/NR的热氧化活化能有所提高,起始热失重温度提高了13.4℃。     

动态固化环氧树脂对芳纶/天然橡胶复合材料界面的改性

在经磷酸(PA)处理的芳纶(AF)表面上涂覆环氧树脂(EP)和固化剂(2E4MZ),用极性端基液体橡胶(LIR)作为EP与天然橡胶(NR)的相容剂,改善AF与NR的界面,并用母炼胶法制备了AF/NR复合材料。通过与NR和单一用磷酸处理AF的复合材料的性能对比发现,AF经过EP和2E4MZ改性后,AF/NR复合材料的硫化速度和交联程度均提高;拉伸强度、撕裂强度和300%定伸应力都显著增强,且当m(EP)/m(AF)为7/100时最佳。动态力学性能测试(DMA)结果表明,EP/2E4MZ处理AF的天然胶具有更高的储能模量和损耗模量;扫描电镜(SEM)分析表明,AF/NR的拉伸断面粗糙,EP和2E4MZ能改善AF与NR的界面粘接。     

碳纳米管/炭黑复配对天然橡胶湿法混炼共沉胶性能的影响

通过制备碳纳米管(CNTs)/炭黑(CB)/天然橡胶(NR)湿法混炼共沉胶,分析碳纳米管与炭黑复配后的共沉胶物理力学性能、硫化性能和动态力学性能,并与传统干法混炼胶进行对比。结果表明,在湿法混炼共沉胶中,随着填料中碳纳米管份数的增大,胶料的焦烧时间及正硫化时间逐渐缩短,其中焦烧时间缩短了11%,正硫化时间缩短了18%。相比于单一填料的补强体系,复配填料体系更有助于2种填料各自的分散。扫描电镜和动态力学性能分析共同显示,复配填料体系在湿法混炼天然胶中分散得更好,且复合材料拉伸强度、撕裂强度和断裂伸长率更高。     

Effect of Multi-Wall Carbon Nanotubes on the Mechanical Properties of Natural Rubber

Multi-walled carbon nanotubes (MWNTs) were used to prepare natural rubber (NR) nanocomposites. Our first efforts to achieve nanostructures in MWNTs/NR nanocomposites were formed by incorporating carbon nanotubes in a polymer solution and subsequently evaporating the solvent. Using this technique, nanotubes can be dispersed homogeneously in the NR matrix in an attempt to increase the mechanical properties of these nanocomposites. The properties of the nanocomposites such as tensile strength, tensile modulus, elongation at break and hardness were studied. Mechanical test results show an increase in the initial modulus for up to 12 times in relation to pure NR. In addition to mechanical testing, the dispersion state of the MWNTs into NR studied by Transmission Electron Microscopy (TEM) in order to understand the morphology of the resulting system     

Effect of multi-wall carbon nanotubes on the mechanical properties of natural rubber

Multi-walled carbon nanotubes (MWNTs) were used to prepare natural rubber (NR) nanocomposites. Our first effort to achieve nanostructures in MWNTs/NR nanocomposites were formed by incorporating carbonnanotubes in a polymer solution and subsequently evaporating the solvent. Using this technique, nanotubess can be dispersed homogeneously in the NR matrix in an attempt to increase the mechanical properties of these nanocomposites. The properties of the nanocomposites such as tensile strength, tensile modulus, tear strength, elongation at break and hardness were studied. Mechanical test results show an increase in the initial modulus for up to 12 times in relation to pure NR. In addition to mechanical testing, the dispersion state of the MWNTs into NR was studied by transmission electron microscopy (TEM) in order to understand the morphology of the resulting system. According to the present study, application of the physical and mechanical properties of carbon nanotubes to NR can result in rubber products which have improved mechanical, physical and chemical properties, compared with existing rubber products reinforced with carbon black or silicone.     

Crosslinked natural rubber nanocomposites reinforced with cellulose whiskers isolated from bamboo waste: Processing and mechanical/thermal properties

Crosslinked natural rubber (NR) nanocomposites were prepared using cellulose nanowhiskers (CNWs) that were extracted from bamboo pulp residue of newspaper production, as the reinforcing phase. The coagulated NR latex containing bamboo nanowhiskers (master batch) was compounded with solid NR and vulcanizing agents using a two-roll mill and subsequently cured to introduce crosslinks in the NR phase. No evidence of micro-scaled aggregates of cellulose nanowhiskers in NR matrix was observed in Scanning Electron Microscopy (SEM) images. The addition of CNWs had a positive impact on the tensile strength, E-modulus, storage modulus, tan delta peak position and thermal stability of the crosslinked NR. Theoretical modeling of the mechanical properties showed a lower performance than predicated and therefore further process optimization and/or compatibilization are required to reach the maximum potential of these nanocomposites.     

Synthesis and characterization of novel hyperbranched polyimides/attapulgite nanocomposites

Novel hyperbranched polyimides/attapulgite (HBPI/AT) nanocomposites were successfully synthesized by in situ polymerization. HBPI derived from novel 2,4,6-tri[3-(4-aminophenoxy)phenyl]pyridine (TAPP) and 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA). 4,4′-diphenylmethane diisocyanate (MDI) modified AT copolymerized with HBPI and the nanocomposites formed multilinked network. Chemical structure, morphology, thermal behavior, and mechanical properties of nanocomposites were investigated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), thermal gravimetric analysis (TGA), dynamic mechanical analysis (DMA), and tensile testing et.al. Results indicated that modified AT was homogeneously dispersed in matrix and resulted in an improvement of thermal stability, mechanical properties and water resistance of HBPI/AT nanocomposites.     

Multi-Wall Carbon Nanotubes/Styrene Butadiene Rubber (SBR) Nanocomposite

A floating catalyst chemical vapor deposition (FC-CVD) method was designed and fabricated to produce high-quality and -quantity carbon nanotubes. The design parameters like the hydrogen flow rate; reaction time and reaction temperature were optimized to produce high yield and purity of Multi-Wall Carbon Nanotubes (MWCNTs). Multi-Walled Carbon Nanotubes (MWNTs) were used to prepare natural rubber (NR) nanocomposites. Our first efforts to achieve nanostructures in MWNTs/styrene butadiene rubber (SBR) nanocomposites were formed by incorporating carbon nanotubes in a polymer solution and subsequently evaporating the solvent. Using this technique, nanotubes can be dispersed homogeneously in the NR matrix in an attempt to increase the mechanical properties of these nanocomposites. The properties of the nanocomposites such as tensile strength, tensile modulus, elongation at break and hardness were studied. Using different percentages of carbon nanotubes from 1 wt% to 10 wt%, several nanocomposites samples were fabricated. Significant improvements in the mechanical properties of the resulting nanocomposites showed almost 10% increase in the Young's modulus for 1 wt% of CNTs and up to around 200% increase for 10 wt% of CNTs.     

Preparation of halloysite nanotubes supported 2-mercaptobenzimidazole and its application in natural rubber

To improve the antioxidative efficiency of 2-mercaptobenzimidazole (MB) and strengthen the interaction between halloysite nanotubes (HNTs) and natural rubber (NR), HNTs supported 2-mercaptobenzimidazole (HNTs-s-MB) was prepared by reacting MB with chlorosilane modified HNTs (m-HNTs). FTIR, XPS and TGA confirmed that MB was chemically bonded onto the surface of HNTs. HNTs-s-MB could be homogeneously dispersed in the NR matrix and there was a strong interfacial interaction between HNTs-s-MB and NR, leading to the better mechanical performances of NR/HNTs-s-MB nanocomposites than those of NR/HNTs nanocomposites. Based on the measurements of the thermo-oxidation activation energy of NR/HNTs-s-MB and NR/m-HNTs/MB nanocomposites containing equivalent antioxidant component, it was found that the antioxidative efficiency of HNTs-s-MB was superior to that of the corresponding low molecular MB owing to the much lower migration and volatility of HNTs-s-MB than those of MB.     

稻壳源白炭黑/炭黑并用对天然橡胶协同补强作用研究

通过扫描电镜观察了稻壳源白炭黑(RHS)在天然橡胶(NR)交联体系中的分散,显示RHS作为刚性补强粒子微观呈纳米尺度均匀分布,这是补强作用的基础。依据非平衡态分子动力学原理,探究了RHS纳米粒子与炭黑(CB)对NR的协同补强作用机理。通过研究双相填料(RHS/CB)对NR协同补强作用,不同的RHS/CB比例对协同补强作用影响较大,适宜的用量比不仅提高物理力学性能,同时改善动态力学性能。     

Synthesis and properties of waterborne polyurethane/attapulgite nanocomposites

The novel nanocomposites derived from waterborne polyurethane (WPU)/Attapulgite (AT) nanocomposites have been successfully synthesized by in situ polymerization progress. AT functionalized by chemical modification were incorporated as a crosslinker in prepolymer. The chemical structures, morphology, thermal behavior, and mechanical properties of the WPU/AT nanocomposites were investigated by Fourier transform infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), X-ray diffraction (XRD) and tensile testing respectively. The experimental results indicated that the organically modified attapulgites were homogeneously dispersed in the WPU and resulted in an improvement of thermal stability, tensile strength and elongation at break of WPU/AT nanocomposites.     

Effect of ZnO nanoparticles doped graphene on static and dynamic mechanical properties of natural rubber composites

In this work, effect of ZnO nanoparticles doped graphene (Nano-ZnO–GE) on static and dynamic mechanical properties of natural rubber composites were studied. Nano-ZnO–GE was synthesized by sol–gel method and thermal treatment. With the incorporation of nano-ZnO–GE into the matrix, the mechanical properties of NR nanocomposite significantly improved over that of NR composite containing with 5 phr of conventional-ZnO. The results demonstrated that the presence of nano-ZnO on the surface of graphene sheets not only conduces to suppressing aggregation of graphene sheets but also acts as a more efficient cure-activator in vulcanization process, with the formation of excellent crosslinked network at low nano-ZnO–GE content. This work also showed that NR/Nano-ZnO–GE nanocomposites exhibited higher wet grip property and lower rolling resistance compared with NR/Conventional-ZnO composite, which makes nano-ZnO–GE very competitive for the green tire application as a substitute of conventional-ZnO, enlarging versatile practical application to prepare high-performance rubber nanocomposites.     

Effect of metal coating of reinforcements on the microstructure and mechanical properties of Al-Al2O3 nanocomposites

The effects of various methods of reinforcement modification on the microstructure and mechanical properties of Al–Al₂O₃ nanocomposites were investigated. Alumina nanoparticles were modified by electroless deposition of Cu, Ni and Co. Subsequently, aluminium matrix nanocomposites reinforced with uncoated and coated nanoparticles were produced by the stir casting method. The results of microstructural analysis showed improved wettability of coated nanoparticles in the molten aluminium alloy. Furthermore, coated nanoparticles exhibited a more desirable interface with the matrix and were homogenously distributed within it. The mechanical properties of the nanocomposites were improving significantly when coated nanoparticles were used as reinforcements. Among the reinforcement modification methods, Ni-coating was recognised as being more effective for improving the mechanical properties of Al–Al₂O₃ nanocomposites.