Thermally induced crosslinking between polyacrylic acid and epoxidized natural rubber. III. Effect of carbon black filler and mixer rotor speed

High-temperature molding of Brabender-mixed blend of polyacrylic acid (PAA) and epoxidized natural rubber (ENR) causes thermally induced crosslinking between PAA and ENR. Studies on Monsanto rheometry of the blend and physical properties, solvent swelling, and dynamic mechanical properties of the molded blend show that both mixer rotor speed and carbon black filler influence the crosslinking between the component polymers. For example, the extent of crosslinking for the 50–50 PAA–ENR blend was found maximum when the component polymers were mixed at 40 rpm, but the same blend filled with 30 phr HAF carbon black filler showed maximum crosslinking when mixing was carried out at 120 rpm. The results have been explained on the basis of formation of network on the filler surface, which in turn depends on two competing factors: increase in bound rubber formation with increase in filler loading at a fixed rotor speed and enhanced degradation of ENR at higher mixer rotor speed at a fixed filler loading. © 1994 John Wiley & Sons, Inc.     

Self-vulcanizable rubber blend systems based on epoxidized natural rubber and chlorosulfonated polyethylene: Effect of blend composition,epoxy content of epoxidized natural rubber,and reinforcing black filler on physical properties

Mill mixed blend of epoxidized natural rubber and chlorosulfonated polyethylene forms a self-vulcanizable rubber blend during molding at high temperatures in absence of any vulcanizing agent, which is confirmed by FTIR studies. The extent of vulcanization reaction not only depends upon time and temperature of molding but also on the level of epoxidation in ENR and its proportion present in the blend. Physical properties of the blends are comparable to that of conventional rubber vulcanizates. Such blends can be reinforced by carbon black filler.     

Effect of HAF carbon black filler on chemorheological behavior of poly(acrylic acid)-epoxidized natural rubber blend

Brabender-mixed blends of poly(acrylic acid) (PAA) and epoxidized natural rubber (ENR) were extruded through the capillary in a Monsanto processability tester, and the capillary pressure versus extrusion time plots were recorded. Constancy in capillary pressure with extrusion time was observed in the case of PAA/ENR blend; but the same blend, filled with HAF carbon black filler, shows a steady increase in capillary pressure with extrusion time. In presence of a free radical acceptor like thiophenol, the rate of capillary pressure rise decreases. Measurements of physical properties, swelling studies, and scanning electron microscopy photomicrography of the extrudates indicates the occurrence of a chemical interaction between physisorbed ENR and chemisorbed PAA. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 135–142, 1997     

Effect of rubber ratio,carbon black level,and accelerator level on natural rubber/bromobutyl rubber blend properties

Statistical experimental design, that is, response surface methodology, was used to predict and explain the effects of rubber ratio, carbon black, and accelerator level on the cure characteristics and physical properties of natural rubber/bromobutyl rubber (NR/BIIR) blends. With these three independent variables, 20 designed compounds were mixed by a two‐roll mill and the scorch time, cure time, cure rate index, together with physical properties (hardness, tensile property, and compression set) were all determined by one operator. Multiple linear regression analysis was used to obtain response equations and thus contour plots, which illustrate the effects of the three independent variables on each property, as shown in detail by the diversity of interactions between independent factors and each property. It was found that the carbon black level is the most significant influential factor on scorch time, cure time, tensile properties, hardness, and compression set. The difference in reactivity toward sulfur vulcanization of NR and BIIR resulted in cure behavior and physical properties that are dominated by the NR content in the rubber ratio factor. Finally, the response equations were shown to be useful for making accurate predictions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3059–3068, 2003     

Co-compatibilising effect of carbon nanotubes and liquid isoprene rubber on carbon black filled natural rubber/polybutadiene rubber blend

Abstract

Bis-(triethoxysilylpropyl)-tetrasulfane functionalised carbon nanotubes (t-CNTs) were used as compatibiliser along with liquid isoprene rubber (LIR) in the natural rubber (NR)/polybutadiene rubber (BR) blend. Their reinforcing and compatibilising effects were evaluated by mechanical, fatigue crack growth resistance properties and blend homogeneity. Scanning electron microscope and transmission electron microscope showed enhanced interfacial adhesion between the binary rubber phases and improved dispersion of the minor phase in the rubber blend respectively with the co-existence of LIR and carbon nanotubes. The tensile strength of the carbon black (CB) filled NR/BR blend reached its optimum when 3 phr CB was replaced with an equal amount of t-CNTs in the presence of 7 phr LIR, while the fatigue crack growth resistance property achieved its maximum in the presence of 3 phr LIR. This interesting co-compatibilisation behaviour of t-CNTs and LIR suggests that t-CNTs have a better effect than CB with the assistance of LIR, which is an effective plasticiser in the NR/BR blend.     

Effect of carbon black/nanoclay hybrid filler on the dynamic properties of natural rubber vulcanizates

In this study, natural rubber (NR) nanocomposites based on carbon black (CB) and two poly(ethylene glycol) (PEG)‐modified clay hybrid filler were fabricated. The morphology and mechanical properties were studied. The dynamic properties of NR vulcanizates were investigated over a range of strain amplitude at two temperatures. It was found that NR with hybrid filler exhibits superior mechanical properties over that with CB as single phase filler. The hybrid filler causes a significant alteration in the dynamic properties of rubber. The Payne effect becomes more pronounced in rubber with modified clay. A decrease in loss factor (tanδ) was observed for rubber with hybrid filler also. The results revealed that the inclusion of nanoclay (NC) could induce a stronger and more developed filler network. Because of the anisotropy of the nanolayers, NC would depress the reconstruction of filler network, or lower the reformation rates when broken down under deformation, giving rise to lower tanδ value at broad temperature range as well as strain amplitude. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of carbon black on self‐crosslinking network structure of polychloroprene rubber and epoxidized natural rubber blends

The goal of this research is to improve poor network structure of polychloroprene rubber (CR)/epoxidized natural rubber (ENR) self‐crosslinking blends, which could substitute traditional vulcanizates in some application area. Carbon black (CB)–CR/ENR blends were prepared by reacting CR with ENR in the presence of CB. The structure of CR/ENR blends was characterized by attenuated total‐reflectance Fourier transform infrared spectroscopy (FTIR‐ATR). The effect of CB loading on curing characterization and mechanical properties of CR/ENR blends was investigated, and the interaction among CR, ENR, and CB was studied using differential scanning calorimetry. The effect of CB loading on the Payne effect of CR/ENR was investigated using rubber process analyzer. Scanning electron microscope was used to characterize the morphology of CB–CR/ENR blends. The results showed that CR/ENR blends were obtained by the ring‐opening reaction of epoxy groups in ENR and chlorine groups in CR. Mechanical properties of CR/ENR blends increased with the increase of CB loading. The Payne effect of CR/ENR became more remarkable with increasing CB loading. Morphology study indicated that interfacial compatibility between CR and ENR increased with the increase of CB loading because CB could strengthen the self‐crosslinking network structure of CR/ENR blends. The promoting effect of CB on self‐crosslinking reaction was verified by the assessment of crosslink density. POLYM. COMPOS., 38:463–471, 2017. © 2015 Society of Plastics Engineers     

Organomodified kaolin as a reinforcing filler for natural rubber

China clay (kaolin) has been modified with sodium salt of rubber seed oil (SRSO). SRSO was characterized using X‐ray diffraction (XRD), infrared spectroscopy (FTIR), and differential thermal analysis (DTA). XRD of the unmodified and SRSO‐modified kaolins showed an increase in the d‐(001) spacing of kaolin platelets from 7.15 to 14 Å. FTIR spectroscopy indicated possible grafting of the organic moiety of rubber seed oil (RSO) onto the clay surface. DTA of the SRSO‐modified kaolin indicated that the SRSO is more strongly bound in a constraint environment within the lamellae of kaolin. Natural rubber (NR) mix containing 10 phr of SRSO‐modified kaolin was found to cure faster than that of a similar mix containing unmodified kaolin. NR vulcanizates containing SRSO‐modified kaolin showed considerable increase in tensile modulus, tensile strength, and elongation at break indicating its potential as an organomodified nanofiller. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effect of carbon black loading on curing characteristics and mechanical properties of waste tyre dust/carbon black hybrid filler filled natural rubber compounds

Curing characteristics, tensile properties, fatigue life, swelling behavior, and morphology of waste tire dust (WTD)/carbon black (CB) hybrid filler filled natural rubber (NR) compounds were studied. The WTD/CB hybrid filler filled NR compounds were compounded at 30 phr hybrid filler loading with increasing partial replacement of CB at 0, 10, 15, 20, and 30 phr. The curing characteristics such as scorch time, t₂ and cure time, t₉₀ decreased and increased with increment of CB loading in hybrid filler (30 phr content), respectively. Whereas maximum torque (M_HR) and minimum torque (M_L) increased with increasing CB loading. The tensile properties such as tensile strength, elongation at break, and tensile modulus of WTD/CB hybrid filler filled NR compounds showed steady increment as CB loading increased. The fatigue test showed that fatigue life increased with increment of CB loading. Rubber–filler interaction, Q_f/Q_g indicated that the NR compounds with the highest CB loading exhibited the highest rubber–filler interactions. Scanning electron microscopy (SEM) micrographs of tensile and fatigue fractured surfaces and rubber–filler interaction study supported the observed result on tensile properties and fatigue life. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Nano ZnO as cure activator and reinforcing filler in natural rubber

Zinc oxide (ZnO) nanoparticles of size 20–90 nm and surface area 9.56 m²/g were synthesized from ZnCl₂ and Chitosan and characterized by X‐ray diffraction, high resolution transmission electron microscopy (HRTEM), and scanning electron microscopy (SEM). Natural rubber (NR) vulcanizates containing nano ZnO was prepared by mill mixing and characterized by SEM, energy dispersive X‐ray analysis (EDAX), and HRTEM. Cure characteristics, free volume studies, bound rubber, crosslink density, and dynamic mechanical properties were evaluated and compared with that of NR vulcanizate containing conventional micro ZnO. Considering the cure characteristics, it was found that NR vulcanizate with 0.5 phr (parts per 100 g rubber) of nano ZnO showed low values of optimum cure time (t₉₀) and very high cure rate index compared with 5 phr of conventional micro ZnO. The study shows that micro ZnO can be successfully replaced with nano ZnO for accelerated sulfur vulcanization process in NR, and preparation of vulcanizate containing nano ZnO with better properties as that of micro ZnO. The optimum dosage of nano ZnO as a cure activator in NR vulcanization was found to be 0.5 phr compared with conventional grade micro ZnO. This will lead to substantial cost reduction in the manufacture of rubber products and alleviate environmental pollution due to excess ZnO in rubber compounds. POLYM. ENG. SCI., 2013 © 2013 Society of Plastics Engineers     

改性炭黑对天然橡胶/顺丁橡胶并用胶性能的影响

采用3种方法对传统炭黑进行表面改性,考察了改性前后炭黑表面形貌及结构的变化,并采用改性炭黑填充天然橡胶（NR）/顺丁橡胶（BR）并用胶,考察了改性炭黑对并用胶力学性能、硫化特性及动态力学性能等的影响。结果表明,与未改性炭黑相比,细化粒径、调高pH值及木质素改性处理后,炭黑表面的粗糙程度增加;且细化改性炭黑具有更高的比表面积,调高pH值改性炭黑具有更多疏松的二次结构,木质素改性炭黑粒径略有增加。对于炭黑填充NR/BR,用细化粒径及调高pH值方法处理的炭黑进行填充,NR/BR硫化胶的力学性能、耐磨性能及抗湿滑性均得到明显改善,但硫化延迟效应明显;木质素改性后,炭黑填充胶的力学性能、耐磨性能均出现不同程度的降低。     

Influence of carbon black filler on the autohesion of polybutadiene rubber

A study of the autohesion of polybutadiene rubber filled with different amounts of carbon black has been made. When the elastomer is uncrosslinked, the autohesive strength initially rises linearly with square root of contact time and finally shows a time independent course. The initial autohesion at time zero increases almost linearly with increasing carbon black content, while the ultimate strength is markedly influenced only when the filler content exceeds 30%. The time necessary to achieve ultimate strength decreases significantly when small amounts of filler are added. Experiments with slightly crosslinked polybutadiene did not show a characteristic time dependence. The autohesive strength increases strongly up to 30% carbon black content and seems to decrease again on further addition of filler.     

Wood flour as a secondary filler in carbon black filled of styrene butadiene/chlorosulphonated polyethylene rubber blend

A study is reported which aims to identify the optimum contents of wood flour (WF) to be introduced into styrene butadiene/chlorosulphonated polyethylene (SBR/CSM) rubber blend compounded with carbon black. A range of composite properties are considered including cure characteristics and mechanical properties, as well as the adhesion strength (rubber‐to‐metal bonding) behavior. Processing characteristic such as maximum torque increases with increasing of the concentration of WF up to 40 phr in SBR/CSM blend, whereas the scorch time and optimum cure time decreases. Results indicated that the tensile strength and tensile modulus, as well as shore hardness of the SBR/CSM composite in which SBR is predominant, increase in a compliance with the increase of WF. Adhesion strength value on peel between metal and WF filled SBR/CSM rubber blend increases when the filling level increases and the maximum value were observed at 40 phr of WF. The enhancement in mechanical properties was supported by data of crosslink density in these samples obtained from swelling measurement. Addition of WF was recommended as an economical and ecological benefit to industries as the properties of the rubber/carbon black composites remained unchanged with increasing WF content. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers.     

Effect of modified carbon black on the properties of natural rubber vulcanizate

Rubber-grade carbon black filler HAF(N330) was modified with a plant product (PP; long aliphatic chain substituted phenols), a proprietary item under patent application, in the presence or absence of hexamine (Hexa) or dicumyl peroxide (DCP) to put a flexible moiety in between the carbon black and the elastomer chain in order to improve some of its processing and reinforcement characteristics in natural rubber (NR). The modification process is simple and involves cheap materials. The modified carbon black was characterized and evaluated for its processability as well as reinforcing characteristics in NR vulcanizate. It was observed to show better processing behavior, without any processing aid, such as easy incorporation and uniform dispersion in the rubber phase without abnormal heat generation, and also improved vulcanizate properties, such as tensile strength, flex cracking resistance, and lower abrasion loss, without affecting other properties to a significant extent. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 683–693, 1997     

不同粒径的碳纳米管补强天然橡胶

以2种不同型号的短多壁碳纳米管（管径OD20-30nm和30-50nm,长度告为0.5-2μm）与炭黑N330混合成复合填料,采用混炼法讨论其对天然橡胶的补强作用。结果表明／碳纳米管对橡胶的拉伸强度、定伸应力、硬度等方面有着显著的影响;不同管径的碳纳米管由于其自身性能的差异,对天然橡胶的性能有不同的影响;碳纳米管的不同添加量对天然橡胶补强的各性能有非常大的影响。     

甲基丙烯酸固态原位接枝改性炭黑对天然橡胶和顺丁橡胶性能的影响

考察了固态原位接枝改性制备的甲基丙烯酸接枝改性炭黑对天然橡胶(NR)和顺丁橡胶。(BR)静态力学性能、动态力学性能的影响。结果表明。甲基丙烯酸改性炭黑比普通商品炭黑填充的NR硫化胶具有更好的静态力学性能;甲基丙烯酸改性炭黑曼有利于降低NR和BR硫化胶的滚动阻力。同时,有利于提高NR硫化胶的抗湿滑性。     

Microwave absorbing properties of carbon black/silicone rubber blend

In the frequency range of 2–18 GHz, the microwave absorbing properties of a carbon black/silicone rubber blend were investigated by changing the carbon black content and the thickness. The real part (ε′) and the imaginary part (ε″) of permittivity of the blends were calculated from the S‐parameters measured by a network analyzer. The reflection loss was simulated by using ε′ and ε″. The reflection loss less than ?10 dB could be obtained in the frequency range of 9.6ε13.5 GHz from the sample with 10 wt% of carbon black at 1.9 mm of thickness.     

Effect of filler–filler interaction on rheological behaviour of natural rubber compounds filled with both carbon black and silica

Rubber compounds are reinforced with fillers such as carbon black and silica. In general, filled rubber compounds show smooth rheological behaviour in measurement of Mooney viscosity or Mooney scorch time. Variation in rheological behaviour was studied in terms of the filler composition using natural rubber compounds filled with both carbon black and silica (carbon black/silica = 60/20,40/40, and 20/60 phr). The compound filled with carbon black/silica of 60/20 phr showed normal rheological behaviour. However, the compounds filled with carbon black/silica of 40/40 and 20/60 phr showed abnormal rheological behaviour, in which the viscosity increased suddenly and then decreased at a certain point during the measurement. The abnormal behaviour was explained by the strong filler–filler interaction of silica. Moreover, the abnormal rheological behaviour was displayed more clearly as the storage time of compounds is increased. © 2003 Society of Chemical Industry     

补强填充剂TBC在橡胶中的应用

试验研究TBC作为补强填充剂在NR，SBR和NBR中的应用效果，并与轻质碳酸钙、白炭黑和炭黑进行对比。结果表明，TBC具有一定补强性，其补强效果优于轻质碳酸钙，不如白炭黑和炭黑，这种差别在NR中不明显，在SBR和NBR中较为明显TBC对NBR物理性能的改善效果较NR和SBR更为明显；TBC在NR，SBR和NBR中的适宜用量分别为40-50，60-70和70-80份。