Effect of nano zinc oxide on the cure characteristics and mechanical properties of the silica‐filled natural rubber/butadiene rubber compounds

With the increasing interest in environmental and health issues, legal restrictions, such as European Union (EU) End of Life Vehicle Directives, were strengthened. This led us to incorporate nano zinc oxide (nano‐ZnO), with particle sizes of 30–40 nm and specific surface areas of 25.0–50.0 m²/g, instead of conventional ZnO into natural rubber (NR)/butadiene rubber (BR) compounds to decrease the content of zinc in the formulation. In the unfilled system, only a 20 wt % nano‐ZnO content, compared to conventional zinc oxide content, showed the cure characteristics and mechanical properties of the same level. This was because the increase in the specific surface area of the nano‐ZnO led to an increase in the degree of crosslinking. The effect of nano‐ZnO on the cure characteristics and mechanical properties was more pronounced in the silica‐filled system than in the unfilled system. This was mainly because of the dispersing agent used in the silica‐filled system, which also improved the dispersion of nano‐ZnO. The silica‐filled NR/BR compounds containing 0.3–3.0 phr of nano‐ZnO showed improved curing characteristics and mechanical properties, such as optimum cure time, 100 and 300% modulus, tensile strength, and tear strength compared to the compound with 5 phr of conventional ZnO. The optimum amounts of nano‐ZnO and stearic acid were only 1.0 and 0.1 phr, respectively. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of Nano CaCO<Subscript>3</Subscript> on thermal properties of Styrene Butadiene Rubber (SBR)

Styrene butadiene rubber (SBR) as matrix was reinforced separately with 9, 15 and 21 nm sizes of CaCO₃, which were synthesized by matrix mediated growth technique. The mixing and compounding was done on two-roll mill and sheets were prepared in compression molding machine. The effect of nature and loading of nano CaCO₃ on these rubber nanocomposites was investigated thoroughly by different characterizations such as DSC, TGA, XRD, and mechanical properties. An appreciable increase in glass transition temperature has been observed from DSC study. 9 nm sizes of CaCO₃/SBR composites show more increment in Tg as compared to pristine SBR as well as different sizes of CaCO₃ filled SBR. This increment in Tg is due to restricted mobility of nano CaCO₃ filled SBR nanocomposites. XRD study of nanocomposites showed that nano CaCO₃ dispersed uniformly throughout the matrix because of the small peak at lower 2θ. This uniform dispersion of nano CaCO₃ contributes towards the higher mechanical properties of rubber composites. From TGA study, it was observed that as the size of CaCO₃ reduces the thermal stability increases as compared to pristine SBR. The other results of these rubber nanocomposites were compared with commercial CaCO₃ filled SBR. Partly this research paper has been presented in International conference on ‘RubberChem 2006, Dec 5–6, 2006, Munich, Germany.     

Preparation of nano‐zinc oxide/EPDM composites with both good thermal conductivity and mechanical properties

In this article, nano‐zinc oxide (ZnO) filled ethylene propylene diene monomer (EPDM) composites are prepared, and the mechanical (static and dynamic) properties and thermal conductivity are investigated respectively, which are further compared with the traditional reinforcing fillers, such as carbon black and nano‐silica. Furthermore, influence of in‐situ modification (mixing operation assisted by silane at high temperature for a certain time) with the silane‐coupling agent Bis‐(3‐thiethoxy silylpropyl)‐tetrasufide (Si69) on the nano‐ZnO filled composites is as well investigated. The results indicate that this novel reinforcing filler nano‐ZnO can not only perform well in reinforcing EPDM but can also improve the thermal conductivity significantly. In‐situ modification with Si69 can enhance the interfacial interaction between nano‐ZnO particles and rubber matrix remarkably, and therefore contribute to the better dispersion of filler. As a result, the mechanical properties and the dynamic heat build‐up of the nano‐ZnO filled composites are improved obviously by in‐situ modification, without influencing the thermal conductivity. In comparison with traditioanl reinforcing fillers, in‐situ modified nano‐ZnO filled composites exhibit the excellent performance in both mechanical (static and dynamic) properties and better thermal conductivity. In general, our work indicates that nano‐ZnO, as the novel thermal conductive reinforcing filler, is suitable to prepare elastomer products serving in dynamic conditions, with the longer expected service life. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation and properties of T300 carbon fiber‐reinforced thermoplastic polyimide composites

In this study, a series of T300 carbon fiber‐reinforced polyimide (CFRPI) composites were prepared by laminating premolding polyimide (PI) films with unidirectional carbon fiber (CF) layers. On the basis of PI systems design, the effect of CF volume fraction, processing conditions, and PI molecular structure on the properties of CFRPI composites was studied in detail. In addition, two kinds of nano‐particles, including carbon nano‐tube (CNT) and SiO₂ were filled into the premolding PI films with different concentrations. And the effect of nano‐particles on the properties of CFRPI composites was also investigated. The surface characteristic of T300 CF was measured by X‐ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The properties of premolding PI film and CFRPI composites were measured by dynamic mechanical analysis (DMTA), SANS testing machine, scanning electron microscopy (SEM), and so forth. These experimental results showed that the properties of CFRPI composites were mainly affected by the premolding PI film and molding condition. The change of CF volume fraction from 55% to 65% took little effect on the mechanical properties of CFRPI composites. In addition, the incorporation of nano‐particle SiO₂ could further improve the properties of CFRPI composites, but CNT hardly improved the properties of CFRPI composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 646–654, 2006     

纳米粒子在氯丁橡胶中的作用

采用硅烷偶联剂WD-40对纳米白炭黑进行改性处理,研究了经过表面改性的纳米白炭黑对氯丁橡胶的补强效果,同时研究了纳米氧化锌对纳米白炭黑补强氯丁橡胶物理机械性能的影响。结果表明,纳米白炭黑对氯丁橡胶具有较好的补强作用,氯丁橡胶的定伸强度、拉伸强度和撕裂强度均随白发黑用量的增加而增加。同普通氧化锌相比,用纳米氧化锌硫化的氯丁橡胶的物理机械性能亦得到了明显提高。     

Fly ash particles and precipitated silica as fillers in rubbers. I. Untreated fillers in natural rubber and styrene–butadiene rubber compounds

In this study, we investigated the effects of untreated precipitated silica (PSi) and fly ash silica (FASi) as fillers on the properties of natural rubber (NR) and styrene–butadiene rubber (SBR) compounds. The cure characteristics and the final properties of the NR and SBR compounds were considered separately and comparatively with regard to the effect of the loading of the fillers, which ranged from 0 to 80 phr. In the NR system, the cure time and minimum and maximum torques of the NR compounds progressively increased at PSi loadings of 30–75 phr. A relatively low cure time and low viscosity of the NR compounds were achieved throughout the FASi loadings used. The vulcanizate properties of the FASi‐filled vulcanizates appeared to be very similar to those of the PSi‐filled vulcanizates at silica contents of 0–30 phr. Above these concentrations, the properties of the PSi‐filled vulcanizates improved, whereas those of the FASi‐filled compounds remained the same. In the SBR system, the changing trends of all of the properties of the filled SBR vulcanizates were very similar to those of the filled NR vulcanizates, except for the tensile and tear strengths. For a given rubber matrix and silica content, the discrepancies in the results between PSi and FASi were associated with filler–filler interactions, filler particle size, and the amount of nonrubber in the vulcanizates. With the effect of the FASi particles on the mechanical properties of the NR and SBR vulcanizates considered, we recommend fly ash particles as a filler in NR at silica concentrations of 0–30 phr but not in SBR systems, except when improvement in the tensile and tear properties is required. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2119–2130, 2004     

Design and preparation of cross‐linked α‐methylstyrene‐acrylonitrile copolymer nano‐particles for elastomer reinforcement

Crosslinked α‐methylstyrene and acrylonitrile (MStAN) copolymer particles in a latex form were synthesized by free radical emulsion polymerization. The particles took a spherical shape with an average size of 53.1 nm in a narrow distribution. When filled into styrene‐butadiene rubber (SBR), nitrile‐butadiene rubber (NBR), and natural rubber (NR), the MStAN nano‐particles exhibited excellent reinforcing capabilities and the best in NBR. By the employment of heat treatment, mechanical properties of the MStAN‐filled SBR composites had got remarkable further improvements. But mechanical properties, together with the morphology, of the MStAN‐filled NBR composites, varied little after heat treatment, which, however, divulged the naturally good compatibility between the MStAN particles and the NBR matrix. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Influence of starch on the properties of carbon‐black‐filled styrene–butadiene rubber composites

The influence of starch on the properties of carbon‐black‐filled styrene–butadiene rubber (SBR) composites was investigated. When the starch particles were directly melt‐mixed into rubber, the stress at 300% elongation and abrasion resistance decreased evidently with increasing starch amount from 5 to 20 phr. Scanning electron microscopy observations of the abrasion surface showed that some apparent craters of starch particles were left on the surface of the composite, which strongly suggested that the starch particles were large and that interfacial adhesion between the starch and rubber was relatively weak. To improve the dispersion of the starch in the rubber matrix, starch/SBR master batches were prepared by a latex compounding method. Compared with the direct mixing of the starch particles into rubber, the incorporation of starch/SBR master batches improved the abrasion resistance of the starch/carbon black/SBR composites. With starch/SBR master batches, no holes of starch particles were left on the surface; this suggested that the interfacial strength was improved because of the fine dispersion of starch. Dynamic mechanical thermal analysis showed that the loss factor at both 0 and 60°C increased with increasing amount of starch at a small tensile deformation of 0.1%, whereas at a large tensile strain of 5%, the loss factor at 60°C decreased when the starch amount was varied from 5 to 20 phr. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Mechanical and flame‐retarding properties of styrene–butadiene rubber filled with nano‐CaCO3 as a filler and linseed oil as an extender

A nanosize CaCO₃ filler was synthesized by an in situ deposition technique, and its size was confirmed by X‐ray diffraction. CaCO₃ was prepared in three different sizes (21, 15, and 9 nm). Styrene–butadiene rubber (SBR) was filled with 2–10 wt % nano‐CaCO₃ with 2% linseed oil as an extender. Nano‐CaCO₃–SBR rubber composites were compounded on a two‐roll mill and molded on a compression‐molding machine. Properties such as the specific gravity, swelling index, hardness, tensile strength, abrasion resistance, modulus at 300% elongation, flame retardancy, and elongation at break were measured. Because of the reduction in the nanosize of CaCO₃, drastic improvements in the mechanical properties were found. The size of 9 nm showed the highest increase in the tensile strength (3.89 MPa) in comparison with commercial CaCO₃ and the two other sizes of nano‐CaCO₃ up to an 8 wt % loading in SBR. The elongation at break also increased up to 824% for the 9‐nm size in comparison with commercial CaCO₃ and the two other sizes of nano‐CaCO₃. Also, these results were compared with nano‐CaCO₃‐filled SBR without linseed oil as an extender. The modulus at 300% elongation, hardness, specific gravity, and flame‐retarding properties increased with a reduction in the nanosize with linseed oil as an extender, which helped with the uniform dispersion of nano‐CaCO₃ in the rubber matrix. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2563–2571, 2005     

Nanocomposites of poly(vinyl chloride) and nanometric calcium carbonate particles: Effects of chlorinated polyethylene on mechanical properties,morphology, and rheology

Nanocomposites of poly(vinyl chloride) (PVC) and nano‐calcium carbonate (CaCO₃) particles were prepared via melt blending, and chlorinated polyethylene (CPE) as an interfacial modifier was also introduced into the nanocomposites through preparing CPE/nano‐CaCO₃ master batch. The mechanical properties, morphology, and rheology were studied. A moderate toughening effect was observed for PVC/nano‐CaCO₃ binary nanocomposites. The elongation at break and Young's modulus also increased with increasing the nano‐CaCO₃ concentration. Transmission electron microscopy (TEM) study demonstrated that the nano‐CaCO₃ particles were dispersed in a PVC matrix uniformly, and a few nanoparticles agglomeration was found. The toughening effect of the nano‐CaCO₃ particles on PVC could be attributed to the cavitation of the matrix, which consumed tremendous fracture energy. The notched Izod impact strength achieved a significant improvement by incorporating CPE into the nanocomposites, and obtained the high value of 745 J/m. Morphology investigation indicated that the nano‐CaCO₃ particles in the PVC matrix was encapsulated with a CPE layer through preparing the CPE/nano‐CaCO₃ master batch. The evaluation of rheological properties revealed that the introduction of nano‐CaCO₃ particles into PVC resulted in a remarkable increase in the melt viscosity. However, the viscosity decreased with addition of CPE, especially at high shear rates; thus, the processability of the ternary nanocomposites was improved. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2714–2723, 2004     

新型无机纳米填料对SBR的补强性能

研究了纳米白炭黑、纳米二氧化钛、纳米氧化铝和白炭黑分别与炭黑并用对SBR的补强性能,并与单独充炭黑进行了对比。试验结果表明,纳米白炭黑／炭黑并用体系能够显提高SBR硫化胶的拉伸性能、热氧老化性能和疲劳性能,而纳米氧化铝／炭黑和纳米二氧化钛／炭黑并用体系能够提高SBR硫化胶的耐磨性。     

复合氧化锌胶料的性能研究

试验研究复合氧化锌对NR和SBR胶料及斜交轮胎胎侧胶和胎面基部胶性能的影响.结果表明,当氧化锌用量超过2.5份后,采用复合氧化锌的NR或SBR胶料硫化特性、物理性能和耐热老化性能与采用间接法氧化锌的胶料接近;采用复合氧化锌等量替代间接法氧化锌用于斜交轮胎,胎侧胶性能变化不大,胎面基部胶物理性能有所提高,胶料成本降低.     

Studies of reinforcement behavior of unique elastomer‐based nanocomposite gels

Unique nanocomposite (NC) gels were prepared by blending water swollen unmodified montmorillonite clay suspension with natural rubber (NR) and styrene‐butadiene rubber (SBR) latices followed by prevulcanization. These were extensively characterized by dynamic light scattering, solvent swelling, tensile, and dynamic mechanical measurements. Reinforcement behavior of NC gels was investigated by adding NC gels into virgin NR and SBR matrices at various loadings. The distribution and morphology of NC gels in the elastomer matrices was studied by X‐ray dot mapping and high‐resolution transmission electron microscopy. Experimental results indicated tremendous improvement of tensile strength (TS) and modulus of the NC gel‐filled matrices along with noticeable changes in dynamic mechanical and rheological properties. Compared with virgin NR, the TS of 16 phr NC gel‐filled NR system increased by 117%. Similar level of enhancement of TS was also registered for the NC gel‐filled SBR systems. NC gel‐filled systems showed higher shear viscosities and lower die‐swell values compared with their virgin counterparts. Contemporary particulate composite and nanofiller reinforcement models were used to understand the reinforcing behavior of these NC gels. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers     

Effect of bamboo charcoal powder on the curing characteristics,mechanical properties,and thermal properties of styrene–butadiene rubber with bamboo charcoal powder

Compounds of styrene–butadiene rubber (SBR) filled with bamboo charcoal powders (BCPs) were prepared with a laboratory‐sized two‐roll mill. The effects of the BCP loading on the curing characteristics and mechanical and thermal properties were investigated. The results indicate that the addition of BCP resulted in a longer curing time and a higher Mooney viscosity in the SBR materials. The incorporation of BCP into SBR improved the mechanical properties and dynamic properties. Furthermore, the mechanical properties of the vulcanizates after thermal aging were also studied, and the experimental results indicate that most of the mechanical properties improved after thermal aging. The overall results indicate that BCP could be used as a cheaper filler for SBR materials. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4534–4541, 2013     

不同粒径氧化锌填充丁腈橡胶的摩擦磨损机制

采用机械共混与热模压工艺制备普通氧化锌(c-ZnO)与纳米氧化锌(n-ZnO)填充丁腈橡胶(NBR)复合材料,并对复合材料的硫化特性、力学性能及摩擦磨损性能进行了对比研究。结果表明,用量相同时,与c-ZnO相比,n-ZnO在硬脂酸与硫黄作用下形成较强硫化剂,可延长胶料的硫化时间,有利于提高胶料的加工安全性与流动性。与加入c-ZnO的胶料相比,n-ZnO/NBR复合材料的撕裂强度提高了11.0%,压缩永久变形减小17.3%,邵尔A硬度略微提高,且在干摩擦、油润滑条件下均表现出优异的耐摩擦磨损性能。c-ZnO/NBR复合材料的磨损机制为磨粒磨损和严重的黏着磨损,n-ZnO/NBR复合材料的磨损机制为磨粒磨损和少量的黏着磨损。     

纳米氧化锌对橡胶性能的影响研究

研究了纳米氧化锌对胶料物理性能的影响。纳米氧化锌因其粒径小,表面积大,吸附活性大,从而具有表面效应和高活性;采用纳米氧化锌可提高胶料的耐磨性,H抽出力和撕裂性能,同时纳米氧化锌可以与橡胶分子实现分子水平上的结合,即纳米材料与橡胶分子的接枝作用,达到提高胶料性能的目的。     

Preparation and performance of high‐impact polystyrene (HIPS)/nano‐TiO2 nanocomposites

High‐impact polystyrene (HIPS)/nano‐TiO₂ nanocomposites were prepared by surface pretreatment of nano‐TiO₂ with special structure dispersing agent (TAS) and master batch manufacturing technology. The results show that when the nano‐TiO₂ content is 2%, the notched impact strength, tensile strength, and elastic modulus of HIPS/nano‐TiO₂ nanocomposites increased to a maximum. This result indicates that nano‐TiO₂ has both toughening and reinforcing effects on HIPS. The heat‐deflection temperature and flame‐retardance of HIPS/nano‐TiO₂ nanocomposites are also obviously improved as the nano‐TiO₂ content is increased. The nanocomposites manufactured by the two‐step method have better mechanical properties than that made by a one‐step method. HIPS/nano‐TiO₂ nanocomposites are also non‐Newtonian and pseudoplastic fluids. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 381–385, 2003     

Polystyrene nanocomposite materials—Preparation,mechanical, electrical and thermal properties,and morphology

This work prepared polystyrene resin nanocomposites with antistatic properties, by melt‐blending polystyrene with nanoscale zinc oxide. The effect of nanoscale zinc oxide on the electrical and physical characteristics of polystyrene nanocomposites was investigated. Two kinds of nanoscale powders, spherical zinc oxide (s‐ZnO) and zinc oxide whisker (w‐ZnO), were selected. The coupling agents, vinyltriethoxysilane and phenyltriethoxysilane, were utilized to improve the compatibility between nanopowders and polystyrene resin. Adding spherical zinc oxide and zinc oxide whisker improved the antistatic characteristic of materials. The surface resistivities of s‐ZnO and w‐ZnO nanocomposite were significantly reduced, by modification with vinyltriethoxysilane and phenyltriethoxysilane. Adding zinc oxide nanopowder increased the flexural modulus and reduces flexural strength. Silane coupling agent improved the flexural properties of nanocomposite. The glass transition temperature and thermal degradation temperature of zinc oxide/polystyrene nanocomposite increased with ZnO content. Treatment with silane increased the glass transition temperature and thermal degradation temperature of composite. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 508–515, 2006     

CaCO3填充型聚丁二烯聚氨酯弹性体的研究

以端羟基聚丁二烯、液化改性二异氰酸(MDI)为原料，用或不用丁二醇作扩链剂，加入CaCO3，用机械搅拌或超声分散法合成填充型聚丁二烯聚氮酯(HTPB-PU)弹性体。并对填充型HTPB-PU弹性体的力学性能、热性能以及水解性能进行了研究，同时用扫描电镜研究了弹性体的应力断裂的断口形态。结果发现，随填料加入量的增多，弹性体的强度增大；填料加入量相同时，纳米CaCO3填充型HTPB-PU弹性体的力学性能和抗水解性能均优于普通CaCO3填充型；采用超声波分散相同时，HTPB-PU弹性体中的CaCO3分散得比采用机械搅拌分散时均匀得多；弹性体中存在明显的两相分离。     

Electrospun nano‐scaled glass fiber reinforcement of bis‐GMA/TEGDMA dental composites

The objective of this study was to investigate the electrospun nano‐scaled glass fiber reinforcement of 2,2′‐bis[4‐(methacryloxypropoxy)‐phenyl]‐propane/triethylene glycol dimethacrylate (Bis‐GMA/TEGDMA) dental composites. The hypothesis was that incorporation of the surface‐silanized electrospun nano‐scaled glass fibers into Bis‐GMA/TEGDMA dental composites would result in substantial improvement on mechanical properties. To test the hypothesis, photo‐cured Bis‐GMA/TEGDMA dental composites filled with various mass fractions of surface‐silanized electrospun nano‐scaled glass fibers were systematically fabricated; and their mechanical properties were then evaluated. The results indicated that small mass fraction substitutions (1, 2.5, 5, and 7.5%) of conventional dental filler with the surface‐silanized electrospun nano‐scaled glass fibers, significantly improved the flexural strength, elastic modulus, and work of fracture values of 70% (mass fraction) filled composites, by as much as 44%, 29%, and 66%, respectively. The mechanical properties of the composites could be further improved by optimizing the chemical compositions and the surface treatment methods of the fibers. We envision that the electrospun nano‐scaled glass fibers could be utilized to develop the next generation dental composites, which would be particularly useful for large posterior restorations. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008