气相白炭黑的比表面积与表面特性对硅橡胶补强效果的影响

探讨了气相白炭黑的比表面积和表面特性对硅橡胶力学性能的影响,同时采用扫描电镜和溶胀法分别研究了不同表面特性白炭黑补强硅橡胶的拉伸断面形貌和交联密度。结果表明：随着疏水性白炭黑比表面积的增加,硅橡胶拉伸强度和断裂伸长率增加;对比发现,疏水性白炭黑的补强效果优于亲水性白炭黑,这是由于疏水性白炭黑在橡胶基体中分散更加均匀,而且疏水性白炭黑补强硅橡胶的交联密度更大。     

Effect of tetraphenylphenyl‐modified fumed silica on silicone rubber radiation resistance

Two kinds of treated fumed silica were prepared by treatment with either tetraphenylphenyltriethoxysilane (TPHTS) or both tetraphenylphenyltriethoxysilane and hexamethyldisilazane (TPHMTS), and were used as reinforcing filler for silicone rubber. The resistance to irradiation of the silicone rubber obtained was investigated by gamma ray of dose 500 kGy in air. The mechanical properties and the average molecular weight between crosslinking points (Mc) of the silicone rubber were determined before and after irradiation. The results show that the fumed silica treated by tetraphenylphenyltriethoxysilane (TPHPHS) can effectively improve the radiation resistance of silicone rubber while the fumed silica treated by both tetraphenylphenyltriethoxysilane and hexamethyldisilazane (MM^N) cannot only effectively improve the radiation resistance of silicone rubber but also has excellent reinforcing effect on silicone rubber. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Influence of the grafting topology of hydrophobic silica surfaces on the mechanical properties of silicone high consistency rubbers

Silica‐filled rubber materials exhibit stress softening and hysteresis under cyclic loadings. These phenomena are usually associated with both the Payne and Mullins effects. To better characterize these properties, five model silicas were produced and used in industrial‐like high consistency rubber (HCR) formulations: the native (hydrophilic) silica and four chemically modified silicas for which both the content of surface silanols and the nature of the grafted silicone chains differ. Silica ? polydimethylsiloxane HCR elastomer with constant silica content and optimal dispersion was tested via static (uniaxial tensile tests, cyclic and monotonic) and dynamic tests. The Payne and Mullins effects as well as the ultimate properties were evaluated as a function of particle surface treatment. It was found that the Payne amplitude decreases with the content of grafted chains, whereas the Mullins effect and ultimate strain decrease with an increase in molar mass between crosslinks. Finally, the ultimate strength is optimal as long as silica is surface treated, albeit independent of surface grafting topology. © 2015 Society of Chemical Industry     

硅烷偶联剂在气相白炭黑表面处理中的应用研究

本文考察了几种不同硅烷偶联剂对气相白炭黑的表面处理效果.对处理前后的气相白炭黑作了FT-IR分析,并用正交试验法考察了处理剂类型、处理时间及处理温度对产品疏水性的影响.结果表明,用18％的HMDS作处理剂,将气相白炭黑在90℃条件下处理4h,所得的疏水性气相白炭黑能很好改善RTV-2硅橡胶的工艺性能和力学性能;另外,采用胶料中直接混合的方式HMDS也能有效改善胶料工艺性能.     

Sol–gel process of alkoxysilanes in an elastomer medium

The influence of different mixtures of di‐, tri‐ and tetraalkoxysilanes on the synthesis and character of silica filler particles prepared by a sol–gel reaction in an elastomer medium was investigated. Silica fillers containing organic substituents with basic properties were synthesized in acrylonitrile–butadiene rubber, with and without carboxyl groups, as well as in decane as a suspension medium, which was treated as an elastomer model. ²⁹Si NMR spectroscopy and scanning electron microscopy (SEM) were used to determine the structure of the resulting silica fillers, and their dispersion in the elastomeric medium. Water, alcohol or other polar solvents were not used in the process of creating the silica fillers as it is impossible to introduce them into the elastomer. Copyright © 2005 Society of Chemical Industry     

改性剂种类对白炭黑补强阻尼硅橡胶性能的影响

以阻尼硅橡胶母胶、气相法白炭黑、改性剂为原料,制成了热硫化阻尼硅橡胶。研究了羟基硅油、六甲基环三硅氮烷、乙烯基三乙氧基硅烷(A-151)、γ-氨丙基三乙氧基硅烷(KH 550)、γ-环氧丙氧基丙基三甲氧基硅烷(KH 560)及其并用对阻尼硅橡胶硫化性能、分散性能、力学性能和黏弹性能的影响。结果表明,硅烷偶联剂类改性剂能显著加快混炼胶的硫化速度、缩短硫化时间;羟基硅油、六甲基环三硅氮烷和KH 560作改性剂时白炭黑的分散效果良好,而采用A 151作改性剂时白炭黑填料网络的Payne效应较明显,但在宽温域(-120~100℃)范围内具有温度稳定性;不同改性剂并用对改善白炭黑分散性没有明显的协同作用;改性剂种类对硫化胶的力学性能影响不大;六甲基环三硅氮烷与KH 560并用时,硅橡胶的阻尼性能最高。     

Immobilization of flame-retardant onto silica nanoparticle surface and properties of epoxy resin filled with the flame-retardant-immobilized silica (2)

To prepare silica nanoparticle having flame-retardant activity, immobilization of flame-retardant onto the surface was investigated. The immobilization of phosphorous flame-retardant was achieved by two-step reactions: (1) introduction of cyclotriphosphazene (PH) groups onto silica nanoparticle by the reaction of terminal amino groups of the surface with hexachlorocyclotriphosphazene and (2) immobilization of bis(4-aminophenoxy)phenyl phosphine oxide (BAPPO) onto silica having PH groups by the reaction of PH groups on the surface with BAPPO. The immobilization of BAPPO was confirmed by FT-IR and thermal decomposition GC–MS. The composite of epoxy resin filled with BAPPO-immobilized silica (Silica–PH–BAPPO) was successfully prepared by heating in the presence of curing agents. Thermal decomposition temperature and glass transition temperature of the epoxy resin filled with Silica–PH–BAPPO was higher than that of epoxy resin filled with untreated silica, free HCTP and BAPPO. Moreover, flame-retardant property of epoxy resin filled with Silica–PH–BAPPO was estimated by limiting oxygen index (LOI). The LOI value of epoxy resin filled with Silica–PH–BAPPO was higher than that of epoxy resin filled with untreated silica, free HCTP and BAPPO. This may be due the fact that char yield of the epoxy resin filled with Silica–PH–BAPPO was higher than that filled with free flame-retardant.     

脱醇型室温硫化硅橡胶的制备

以α,ω-二羟基聚二甲基硅氧烷为基胶,氨基硅烷JT-908为封端剂,添加气相法二氧化硅、交联剂、硅烷偶联剂和催化剂制得脱醇型室温硫化硅橡胶,研究了封端剂和气相法二氧化硅用量、催化剂种类和用量、硅烷偶联剂种类对硅橡胶性能的影响.结果表明,封端剂的较佳用量为4份,气相法二氧化硅的较佳用量为10份,催化剂选择二月桂酸二丁基锡...     

Thermo-mechanical properties of high density polyethylene – fumed silica nanocomposites: effect of filler surface area and treatment

High density polyethylene was melt compounded with various untreated (hydrophilic) or surface treated (hydrophobic) fumed silica nanoparticles, having different surface areas. The thermo-mechanical properties of the resulting nanocomposites have been thoroughly investigated. Field emission scanning electron microscopy revealed that nanofiller aggregation was more pronounced as the silica surface area increased, while nanofiller dispersion improved with a proper filler functionalization. The homogeneous distribution of fumed silica aggregates at low filler content allowed us to reach remarkable improvements of thermal stability, evidenced by an increase of the degradation temperature and a decrease of the mass loss rate with respect to neat matrix, especially when surface treated nanoparticles were utilized. Interestingly, the stabilizing effect produced by fumed silica nanoparticles was accompanied by noticeable enhancements of the ultimate tensile mechanical properties, both under quasi-static and impact conditions. Concurrently, a progressive enhancement of both elastic modulus and tensile stress at yield with the filler amount, was observed.     

气相法白炭黑的特性及其在硅橡胶中的应用

简述了气相法白炭黑的发展及国内生产情况，介绍了气相法白炭黑的结构和表面性质，以及在热硫化硅橡胶和室温硫化硅橡胶中的应用。     

Bound rubber and “crepe hardening” in silicone rubber

Some recent results of the research aimed to correlate properties of filled silicone rubber compounds with surface properties of fumed silica fillers are reported. It is shown that the specific interaction between silica surface silanol groups and the siloxane chain of silicone rubber plays the main role in “crepe hardening” and bound rubber formation in compounds. The silanol coverage of silica determines the tightness of polymer–filler network in bound rubber. The experimental data fit Meissner's theory of bound rubber quite well. Remilling of “crepe hardened” compounds was also studied, and the structure of the remilled compounds is proposed. The activation energy of bound rubber formation on mixing was found to be 16.8 kj/mole; this suggests that physical rather than chemical processes are involved in the interaction between silica and silicone rubber.     

影响HTV硅橡胶撕裂强度的因素

考察了白炭黑种类、羟基硅油用量、含氢硅油用量以及不同乙烯基含量生胶并用对热硫化(HTV)硅橡胶撕裂强度的影响。结果显示,气相法白炭黑的补强效果强于沉淀法白炭黑,且比表面积越大,硅橡胶的撕裂强度越高;随着羟基硅油加入量的增加,硅橡胶的撕裂强度先增后趋于稳定;含氢硅油的用量对HTV硅橡胶的撕裂强度基本没有影响;高乙烯基含量生胶和低乙烯基含量生胶并用能显著提高HTV硅橡胶的撕裂强度。较佳配方是:166 g 110-0生胶,4 g 112生胶、80 g QS-102气相法白炭黑、8.5 g羟基硅油、1.0 g含氢硅油、0.5 g乙烯基硅油,此时,HTV硅橡胶的撕裂强度达到21 KN/m。     

硅油和白炭黑比表面积对硅橡胶性能的影响

气相法白炭黑是硅橡胶补强的最佳填料,羟基硅油是硅橡胶补强中常用的1种结构控制剂。本文研究了羟基硅油的用量以及气相法白炭黑比表面积对硅橡胶力学性能的影响。结果表明:随着羟基硅油用量的增加,硅橡胶的硬度、拉伸强度均逐渐降低,而断裂伸长率却随羟基硅油用量的增加而逐渐增大;随着气相法白炭黑比表面积的增大,硅橡胶的硬度、拉伸强度逐渐增大,而断裂伸长率逐渐减小。     

Comparative Properties of Hydrophilic and Hydrophobic Fumed Silica Filled Two-Component Polyurethane Adhesives

Two fumed silicas, one hydrophilic and another hydrophobic, were added to a two-component polyurethane (PU) adhesive and their properties compared. The filled polyurethanes were characterized by thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), transmission electron microscopy (TEM), and water and diiodomethane contact angle measurements. The adhesive strength was evaluated from single lap-shear tests of solvent wiped stainless steel/polyurethane adhesive joints. The fumed silicas were well-dispersed in the polyurethane matrix as bundles of nanometric spherical silica particles. However, some micron size agglomerates of fumed silica appeared in the filled polyurethane. The addition of fumed silica favoured the degree of phase separation between the hard and the soft segments in the polyurethane. The polyurethanes were not fully cured under the conditions used in this study and the addition of fumed silica inhibited the curing reaction; the extent of the curing reaction was not affected by the hydrophilic or hydrophobic nature of the fumed silica. The filled polyurethanes were further cured during DSC experiments and this was noticed by the appearance of the melting of the hard segments and the displacement of the second glass transition to a higher temperature. On the other hand, the addition of fumed silica increased the wettability and the surface energy of the polyurethane; this increase was mainly due to an increase in the polar component of the surface energy. The increase in surface energy is somewhat more marked in the case of the hydrophilic silica filled polyurethane, indicating that the polarity of the fumed silica affected the surface properties of the polyurethane. Finally, the addition of the hydrophilic fumed silica increased the adhesion of the filled polyurethane adhesive to stainless steel which was in agreement with the higher surface energy of the hydrophilic fumed silica filled polyurethane.     

Polymer nanocomposite powders and melt spun fibers filled with silica nanoparticles

Nanocomposite powders from polypropylene filled with surface modified and unmodified fumed silica have been prepared from polymer solution to achieve improved mixing and have been forwarded to fiber melt spinning. The surface of the fumed silica was modified with dodecyl alkoxy silanes. Crystallization velocity and viscosity of the PP nanocomposites thereof were determined to ensure good melt spinning processing conditions for all composite compositions. Upon addition of untreated filler particles, a shear thinning and an increased crystallization velocity of the polymer melt was found, while only minor changes were detected in the presence of surface modified fumed silica particles. The composites and the polymer fibers made from these powder composites by melt spinning were mainly characterized by optical microscopy (OM), scanning electron microscopy (SEM), mechanical measurements, differential scanning calorimetry (DSC), and solid‐state NMR. The unmodified fumed silica was found to have a strong influence on the mechanical fiber properties, while the surface modified silica only a small one. Fibers were additionally characterized with respect to the uniformity, the PP crystallinity, moisture absorption, and the water contact angle. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 218–227, 2007     

单组分硅酮密封胶的研制及性能研究

以107硅橡胶为基胶,以气相白炭黑为补强填料,甲基硅油为增塑剂,制备了单组分硅酮密封胶,研究了基胶的含量、气相白炭黑的性质和添加量、增塑剂的用量等对密封胶性能的影响.实验结果表明,在基胶含量为60％左右,气相白炭黑比表面积为150 m2/g,添加量为10％左右,增塑剂量为26％左右时可获得较理想的综合性能.     

聚碳酸酯微粉/气相白炭黑杂化增强硅橡胶

利用磨盘形力化学反应器常温粉碎制备了聚碳酸酯（PC）微粉，在硅橡胶的常规补强体系中，引入PC微粉部分代替白炭黑，实现了对硅橡胶的杂化增强，在一定程度上改善了硅橡胶复合材料的力学性能。考察了PC微粉添加量、粒径以及表面处理白炭黑对硅橡胶复合材料力学性能的影响。结果表明，用PC微粉部分代替白炭黑，可以大幅度提高硅橡胶复合材料的断裂伸长率，从230％提高到最大320％左右，撕裂强度从12．3kN／m提高到最大14．6kN／m，复合材料的硬度显著降低，从78降低至68，白炭黑经硅烷偶联剂处理后，硅橡胶复合材料的硬度减小为63。     

Rheological behaviors of fumed silica/low molecular weight hydroxyl silicone oil

The structure and viscoelastic properties of fumed silica gels in low molecular weight hydroxyl silicone oil were investigated by means of steady and dynamic rheology. It is found that the fumed silica/hydroxyl silicone oil suspension exhibits shear‐thickening under steady shear and “strain‐thickening” under oscillatory shear condition. Effects of hydroxy groups on the rheological behavior of silicone oil suspension with highly dispersed hydrophilic amorphous silica were investigated by infrared, ¹H‐NMR, and rheological test. The results show that the hydroxy groups on this system play an important role on the formation of shear thickening behavior of the suspension solution. At the same particle diameter and mass fraction, the amount of hydroxy groups on this system has a strong effect on increasing the viscosity of the suspension, which is likely due to multiassociation hydrogen bonding between liquid molecules and silanol groups on fumed silica surfaces (Si? OH). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40722.     

硅橡胶模具胶生产工艺及加工设备的选择

介绍了硅橡胶模具胶的生产工艺及反应釜、高速混合机、行星搅拌机、捏合机等几种用于硅橡胶模具胶生产的设备。经比较发现采用湿法工艺对白炭黑进行表面处理时，捏合机是较适合的设备。     

Synthesized graphene oxide and fumed aerosil 380 dispersion stability and characterization with partially hydrolyzed polyacrylamide

Hydrolyzed polyacrylamide(HPAM)is a commonly used polymer for the chemicals,mining and refining processes of hydrocarbon but suffers from a persistent high-temperature instability problem.In contrast,the nanoparticle suspension remains a technical challenge because of the strong interactions of van der Waal forces within nanoparticles,which always encourage aggregation.This research sought to improve nanoparticles(NP)stability and polymer(HPAM)rheological properties to improved hydrocarbon recov-ery by utilizing synthesized graphene oxide(GO)nanosheets and fumed Aerosil 380 Silica oxide(SiO2).The aqueous nanocomposites based on HPAM-GO and HPAM-SiO2 in aqueous polymeric solutions have been developed,and its viscoelastic and static behaviour is studied.The results imply that by adding fumed silica NP,the viscoelastic behaviour of HPAM is marginally improved,particularly in high temper-atures and salinity,however,the inclusion of GO's significantly improves the viscosity and stability of the base polymer fluid at high temperatures.The Fourier data for the transformation of the infrared spectrum confirmed that the hydrogen bonding formed between HPAM carbonyl groups and silica NP surface sila-nol functionality and covalent interlinking of electrostatic h-bonding between HPAM and functional GO contributed to the improved stabilization and improved rheological performance that helps to recover high salinity and temperature hydrocarbons.