Effect of titanate coupling agent on the mechanical,thermal, dielectric,rheological, and morphological properties of filled nylon 6

Fillers are used along with various commodity as well as engineering polymers to improve the properties of polymers. The performance of filled polymers is generally decided on the basis of the interface attraction of filler and polymers. Fillers of widely varying particle size and surface characteristics are responsive to the interfacial interactions with polymers. The present study deals with the effect of a coupling agent, tetra isopropyl titanate (TPT), on the properties of flyash filled nylon 6. It is observed that tensile strength, impact strength, and heat distortion temperature improved with the addition of TPT as compared to without the coupling agent filled nylon 6. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 266–272, 2006     

偶联剂对白炭黑／SBR复合材料力学性能的影响

研究了4种偶联剂KH-550、KH-792、WD-60和HG-305对白炭黑／SBR复合材料力学性能和热空气老化性能的影响。研究结果表明：当KH-550用量为4．0份时,复合材料的综合力学性能最好,与未改的白炭黑／SBR复合材料相比,其拉伸强度和撕裂强度分别提高了77％和24％;复合材料的老化实验结果表明,经偶联剂改性的复合材料的耐热老化性能有所下降,其中HG-305改性的复合材料抗老化性较好。     

Effects of nanoclay and coupling agent on the physico‐mechanical,morphological, and thermal properties of wood flour/polypropylene composites

This article presents the effects of coupling agent and nanoclay (NC) on some properties of wood flour/polypropylene composites. The composites with different NC and maleic anhydride grafted polypropylene (MAPP) contents were fabricated by melt compounding in a twin‐screw extruder and then by injection molding. The mass ratio of the wood flour to polymer was 40/60 (w/w). Results showed that applying MAPP on the surface of the wood flour can promote filler polymer interaction, which, in turn, would improve mechanical properties of the composite as well as its water uptake and thermal stability. Composite voids and the lumens of the fibers were filled with NC, which prevented the penetration of water by the capillary action into the deeper parts of composite. Therefore, the water absorption in composites fabricated using NC was significantly reduced. Scanning electron microscopy has shown that the treatment of composites with 5 wt% MAPP, promotes better fiber–matrix interaction, resulting in a few numbers of pull‐out traces. In all cases, the degradation temperatures shifted to higher values after using MAPP. The largest improvement on the thermal stability of composites was achieved when NC was added. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers     

Effect of processing routes on the mechanical, thermal and morphological properties of PLA-based hybrid biocomposite

Due to environmental awareness and depletion of petroleum oil, bioplastics and their composites are one of the most researchable topics throughout the world. Polymers that are produced from renewable sources are expected to be the best alternative to replace conventional polymers. The bottles neck of these bioplastics is its cost which limits its application in certain purposes. Bioplastics filled or reinforced with natural fibers can reduce cost and improve properties, like stiffness, strength and toughness of biocomposites. Impact strength and fracture toughness are the main demerits of short fiber-filled biocomposite. On the other hand, when nanoclay, having a very high aspect ratio, is mixed with bioplastics it may significantly affect the thermal and mechanical properties of the final composites. A composite may also suffer dispersion inefficiency, which is considered the key factor to improve the properties. The aim of this paper was to hybridize nanoclay and short kenaf fiber in polylactic acid (PLA) by double extrusion method and followed by mechanical, thermal and morphological characterizations. Mechanical properties showed improvement with nanoclay, specifically the impact strength increased more than 50 % compared with unreinforced PLA. A double extruded composite showed 3–10 % better tensile and flexural properties than the single extruded composite. Similarly, addition of nanoclay increased decomposition and melting temperatures (T _m) from 198 to 225 °C and 152 to 155 °C, respectively. Crystallization temperature (T _c), however, dropped with nanoclay from 116 to 106 °C and storage modulus (E’) increased by about 1 GPa. These findings were also supported by scanning electron micrograph (SEM) and transmission electron micrograph (TEM) where in double extruded composite a better dispersion of nanoclay was observed. By employing X-ray diffraction (XRD) it was found that higher percentage of crystallinity was obtained while Fourier transform infrared (FTIR) displayed new bond formation. The presence of nanoclay enhanced thermal and mechanical properties of the hybrid composite.     

Influence of silica loading on the mechanical properties and resistance to oil and thermal aging of CR/NR blends

Blends of 75/25 chloroprene rubber(CR)/natural rubber (NR) filled with various loadings of precipitated silica were prepared and their processability and mechanical properties as well as their resistance to thermal aging and oil were determined. The blend morphology was also studied using the atomic force microscopy technique. The results reveal that the mixing energy and the Mooney viscosity of the compound are increased continuously with increasing silica loading. It is also found that both scorch and optimum curing times are shortened while the total crosslink density is increased with increasing silica loading. The positive effect on cure could be explained by the chemical reaction between the allylic chlorine atom of CR and the silanol group on silica surface. The tensile strength, modulus, and hardness of the blend vulcanizate are noticeably improved while the compression set at elevated temperature is impaired with increasing silica loading. The results also reveal that both thermal aging resistance and oil resistance of the blend vulcanizates, as represented by the relative properties, are enhanced with the addition of silica. The resistance enhancement is believed to arise from the combination of the dilution effect, the increased crosslink density and also the reduction of NR dispersed phase size. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Effect of silane coupling agent on swelling behaviors and mechanical properties of thermosensitive hybrid gels

A series of organic–inorganic hybrid thermosensitive gels with three different structures were prepared from N‐isopropylacrylamide (NIPAAm), and N, N′‐methylenebisacrylamide (NMBA) and tetraethoxysilane (TEOS) [N‐IPN]; NIPAAm, 3‐(trimethoxysilyl) propyl methacrylate (TMSPMA) as coupling agent and TEOS [NT‐IPN]; and NIPAAm, TMSPMA, and TEOS [NT‐semi‐IPN] by emulsion polymerization and sol–gel reaction in this study. The effect of different gel structures and coupling agent on the swelling behavior, mechanical properties, and morphologies of the present gels was investigated. Results showed that the properties of the gels would be affected by the gel networks such as IPN or semi‐IPN and with or without existence of TMSPMA as the bridge chain between networks. The NT‐semi‐IPN gel had higher swelling ratio and faster diffusion rate because poly(NIPAAm) moiety in the semi‐IPN gels was not restricted by NMBA network. However, the IPN gels such as N‐IPN and NT‐IPN had good mechanical properties and lower swelling ratio, but had a poor thermosensitivity due to the addition of coupling agent, TMSPMA, into the gel system that resulted in denser link between organic and inorganic components. The morphology showed that IPN gels had partial aggregation (siloxane domain) and showed some denser phases. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effect of silanes on the morphology,hydrophobicity, and dynamical mechanical properties of polyimide/silica hybrid membranes

Polyimide (PI)/silica hybrid membranes with high contact angles were prepared through the in situ sol–gel process. The precursor, poly(amic acid) with controlled block chain length, was synthesized using 4,4′‐diaminodiphenyl ether (ODA), 3,3′,4,4′‐benzophenone‐tetracarboxylic dianhydride (BTDA) and 3‐aminopropyl‐trimethoxysilane (APrTMOS) or 3‐aminopropyldimethylethoxysilane (APDiMOS). And then, phenyltrimethoxysilane (PTS) or tetramethoxysilane (TMOS) or methyltrimethoxysilane (MTrMOS) was respectively, added to the above polyamic acid and mixed thoroughly. Following curing reaction, the PI/silica hybrid membranes with different cross‐linkages, silica content, and hydrophobic properties were prepared. The effect on the formation of PI imide ring during imidization reaction is increased as the increase of silanes content and characterized by frequency shiftment and absorbance ratio of Fourier transform infrared (FTIR) measurements. All the hybrid membranes show high transparency though with high silica contents. The storage modulus, tan δ, and damping intensity by DMA measurements are all correlated with silane content or block chain length. And all these membranes with silane content possess high contact angle as compared to pure PI without any silanes added and the contact angles increase with increasing the silane content. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

硅烷偶联剂对原位生成二氧化硅/NR复合材料性能的影响

研究硅烷偶联剂对原位生成二氧化硅粒子特征和原位生成二氧化硅／NR复合材料性能的影响。结果表明，在溶胶-凝胶反应中加入硅烷偶联剂，原位生成的二氧化硅粒子表面积减小，表面羟基减少，分散较好；在混炼过程中添加硅烷偶联剂，原位生成二氧化硅／NR复合材料的物理性能有明显提高，其中添加硅烷偶联剂A的复合材料物理性能、耐磨性能和耐疲劳性能较好；添加偶联剂Si75的复合材料耐磨性能较好。     

Jatropha deoiled cake filler‐reinforced medium‐density polyethylene biocomposites: Effect of filler loading and coupling agent on the mechanical,dynamic mechanical and morphological properties

This work focuses on the performance of Jatropha deoiled cake (JOC) as filler for medium‐density polyethylene. The biocomposites were prepared using a melt‐compounding technique. Maleated polyethylene (MPE) was used as a reactive additive to promote polymer/filler interfacial adhesion. The mechanical, thermodynamic mechanical and morphological properties of the resultant composites were investigated. The results show that the incorporation of JOC into the matrix reduced tensile, flexural, and impact strengths compared with the pure matrix. Moreover, tensile and flexural moduli were increased. The composites prepared with MPE had better mechanical properties and lower water uptake, indicating an enhancement in the interfacial interaction between JOC and polyethylene systems. The storage modulus was increased by the increase in filler loading and decreased when MPE was used. The composites loss modulus curves revealed two glass transitions indicating partial miscible blends. Scanning electron microscopy analysis for maleated composites showed a relatively homogeneous morphology with few left cavities, and the filler particle size is smaller compared to nontreated composites. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers     

Effects of silane coupling agent hydrophobicity and loading method on water absorption and mechanical strength of silica particle-filled epoxy resin

A suitable silane coupling agent (SCA) structure to improve the water absorption and mechanical strength of silica particle-filled epoxy resin was investigated. Bonding, hydrocarbon, and fluorocarbon type SCAs were employed. The bonding type has glycidoxy or amino groups that react with epoxy resin, whereas the other types have only hydrophobic chains. The spherical silica particles were added to epoxy resin at amounts from 10 to 50 wt %. The effect of water absorption was consequently lowered in the order of hydrocarbon > bonding types. The fluorocarbon type SCA was also effective at zero and low silica content. Modification of the epoxy phase by SCA addition was clarified to have a more dominant effect than the adhesion of silica/epoxy interface for the lowering of water absorption, whereas it had been conventionally considered that interfacial adhesion had a more dominant effect. The mechanical strength was higher for the bonding type than the other type. Two addition methods were compared, a pretreatment method and an integral blend method in which all components were mixed simultaneously. The integral blend method was determined to be superior to the pretreatment method for both water absorption and mechanical strength, which was also contrary to the conventional view. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48615.     

偶联剂Si69改性白炭黑对NR/SSBR并用胶性能的影响

试验研究偶联剂Si69用量和白炭黑改性方法对白炭黑填充NR/SSBR并用胶性能的影响.结果表明,当采用直接加入法改性白炭黑时,随着偶联剂Si69用量的增大,Payne效应减弱,NR/SSBR并用胶的t10延长,t90缩短,硫化胶的物理性能提高,偶联剂Si69用量以4 5份为宜.与直接加入法改性白炭黑填充并用胶相比,预处理法改性白炭黑填充并用胶的Payne效应减弱,拉伸强度和撕裂强度增大;高温静置处理法改性白炭黑填充并用胶的定伸应力、拉伸强度和损耗模量增大.     

Influence of hydration on the mechanical,structural, thermal,and morphological properties of cement filled epoxy composites

Different loading of Portland cement (PC) (10, 20, 30, and 40 wt%) was used to produce epoxy-based polymer concrete. The optimum loading was used to prepare another sample using hydration in presence of air circulation. The polymer concretes were characterized in terms of mechanical, thermal, structural and morphological properties. The properties showed increasing trends after cement addition. Results showed that the tensile strength of the polymer concretes were improved by 37.2%, 115.5%, 165.9%, and 40.6% for loading of 10, 20, 30, and 40 wt% cement, respectively. In addition, the flexural strength of the polymer concretes was also enhanced and found maximum (175.3% higher) in 30 wt% concrete compared to neat epoxy. Other mechanical properties of the polymer concrete were also found increasing. Moreover, decomposition temperature was raised nearly 15°C for adding 30 wt% cement which was the maximum among the other polymer concretes. For the case of hydration in presence of air circulation, the prepared composite showed the highest tensile mechanical performance with improved surface topography. From the results, it was concluded that the addition of cement into the epoxy was very effective to produce polymer concretes.     

Influence of silane‐coupling agents on the performance of morphological,mechanical, thermal,electrical, and rheological properties of polycarbonate/fly ash composites

Fly ash, waste product of thermal power station, generated in huge quantities has been posing problems of its disposal. As such, it contains a variety of inorganic oxide and is available in finely powder form. Attempts have been made for its utilization, as filler in engineering plastic. The fly ash (FA) fillers reinforced polycarbonate (PC) composites were fabricated using a economically and environmentally viable method of melt extrusion and compression molding technique. The FA surface was chemically modified using vinyltrimethoxysilane and 3–Aminopropyltriethoxysilane. The feasibility of using treated FA/PC composites was examined in terms of scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, and rheological behavior. The morphology shows a good dispersion and strong interfacial interaction between PC and modified FA than the unmodified counterpart. Mechanical investigation manifested that modified FAs have strengthening effect (increase in tensile and flexural strength) on the mechanical performance of PC composites. Rheological behavior of PC/FA composites was characterized by parallel plate rheometer system. Addition of treated FA imparted dimensional and thermal stability, which has been observed in scanning electron micrographs and in thermogravimetric analysis plot. The increase of thermal stability has been explained based on increased mechanical interlocking of PC chains inside the structure of FA. This study shows that surface modification of FA is one of the key factors influencing the mechanical and thermal properties of PC/FA composites. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Influence of in situ‐generated silica nanoparticles on EPDM morphology,thermal, thermomechanical,and mechanical properties

Silica nanoparticles were synthesized by means of a sol–gel method and generated in ethylene propylene diene monomer rubber (EPDM) by in situ synthesis. The properties were determined using scanning electron microscopy, attenuated total reflectance Fourier‐transform infrared spectroscopy, thermogravimetric analysis, tensile testing, dynamic mechanical analysis, swelling tests, and gel content determination. The silica particles were homogenously dispersed in the EPDM matrix, with the presence of agglomerates, especially for high silica contents. The swelling experiments showed a decrease in the crosslinking density of the vulcanized rubber due to the presence of the silica nanoparticles. The mechanical properties, however, were significantly improved by the presence of the stiff silica nanoparticles. The effect of the amount of silica on the thermomechanical properties and thermal degradation of EPDM was also investigated. The presence of silica showed an increase in the storage and loss moduli at high temperatures, probably due to the increasing filler content. The thermal degradation analysis showed that the presence of silica particles incorporated in the EPDM matrix had no significant influence on the thermal stability of the composites. POLYM. COMPOS., 36:825–833, 2015. © 2014 Society of Plastics Engineers     

Influence of nano silica hybrid expandable graphite on flammability,thermal stability,and mechanical property of polypropylene/polyamide 6 blends

Silica (SiO₂) nanohybrid expandable graphite (nEG) particles fabricated through one-step method are used as an efficient flame retardant for polypropylene (PP)/polyamide 6 (PA6) blends. The effect of nEG on the flammability, thermal stability, crystallization behaviors, and mechanical properties of PP/PA6 composites is investigated by using limit oxygen index (LOI), UL-94 test, cone calorimeter test (CCT), thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared, scanning electron microscopy, and mechanical tests. Compared with pure expandable graphite (EG), nEG improves the flame retardancy of composites. The results of LOI show that LOI of PP/PA6/nEG10 and PP/PA6/nEG15 composites are 26.0% and 27.2%, respectively. But the LOI values of PP/PA6/EG10 and PP/PA6/EG15 composites are 25.7% and 26.9%, respectively. The UL-94 test results show that PP/PA6/nEG10 composites reach V-1 level when the nEG content is only 10%. However, the PP/PA6 composites with 10% EG does not pass the UL-94 test. In addition, PP/PA6 composites with 15% nEG can reach V-0 level. The CCT results further show that nEG has a higher flame-retardant efficiency than pure EG for PP/PA6 blends. The thermal stability of PP/PA6/nEG composites is better than that of PP/PA6/EG composites. The mechanical property tests indicate that nEG is more conducive to maintain the tensile and impact strengths of PP/PA6 blends than EG due to the enhanced compatibility and interfacial adhesion.     

Influence of nanoclay and coupling agent on the physical and mechanical properties of polypropylene/bagasse nanocomposite

In this work, the effects of nanoclay (1–4 wt %) and coupling agent (2 and 4 wt %) loading on the physical and mechanical properties of nanocomposites are investigated. Composites based on polypropylene (PP), bagasse flour, and nanoclay (montmorillonite type) was made by melt compounding and then compression molding. When 1–3 wt % nanoclay was added, the tensile properties increased significantly, but then decreased slightly as the nanoclay content increased to 4%. The impact strength was 6% lower by the addition of 1 wt % nanoclay, it was decreased further when the nanoclay content increased from 1 to 4%. Finally, the water absorption of PP/bagasse composites was lowered with the increase in nanoclay content. Additionally, the coupling agent, 4 wt % MAPP, improved the mechanical and physical properties of the composites more than the 2 wt % MAPP. From these results, we can conclude that addition of nanoclay enables to achieve better physical and mechanical properties in conventional composites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

偶联剂Si69原位改性白炭黑对SSBR胶料性能的影响

研究偶联剂Si69原位改性白炭黑对SSBR胶料性能的影响.结果表明,偶联剂Si69原位改性白炭黑可以降低SSBR混炼胶的门尼牯度.减弱混炼胶的Payne效应,改善混炼胶的加工性能;其在SSBR硫化胶中的分散度提高,且分散均匀,可以降低硫化胶的邵尔A型硬度,提高硫化胶的300%定伸应力.动态粘弹性能分析表明,偶联剂Si69原位改性白炭黑可降低60℃下、多次应变及大应变、宽频率范围内SSBR硫化胶的滞后损失.动态热力学分析表明,偶联剂Si69原位改性白炭黑可以提高SSBR硫化胶在0℃左右的损耗因子,从而提高胶料的抗湿滑性能.     

The effect of nanosilica on mechanical,thermal and morphological properties of epoxy coating

In this study, nanosilica of very high specific surface area is used as reinforcing filler for preparing an epoxy-based nanocomposite coating. For appropriate dispersion of nanoparticles in the polymer matrix, ultrasound waves were applied after mechanical mixing. The resulting perfect dispersion of nanosilica particles in epoxy coating revealed by transmission electron microscopy ensured the transparency of the nanocomposite. Nanoindentation was used to determine some mechanical properties such as hardness and elastic modulus. The obtained results show 26 and 21% increases in hardness and elastic modulus, respectively for resin filled with 5% nanosilica compared to neat epoxy. DMA results show that the glass transition temperature of samples is increased with increasing silica nanoparticles. The result of TGA shows significant improvement of the thermal decomposition temperature of epoxy coating containing 5% nanosilica compared to neat epoxy. Scanning electron microscopy (SEM) micrographs of fractured surfaces show increased roughness with nanosilica addition.     

Influence of polyhedral oligomeric silsesquioxanes on thermal and mechanical properties of polycarbonate/POSS hybrid composites

Two types of silsesquioxanes were synthesized by hydrolytic condensation reaction, and then were incorporated into polycarbonate (PC) matrix by melt blending to prepare PC/POSS hybrid composites. The study of morphology of the composites showed that octaphenylsilsesquioxane (PH‐POSS) exhibited partial compatibility with PC matrix, while 3‐glycidyloxypropylsilsesquioxane (EP‐POSS) could react with phenolic hydroxyl groups of matrix. Thermal and mechanical properties were studied by DSC, TGA, and DMA. The result showed that the incorporation of POSS not only improved thermal stabilities of PC composites, but also retarded their thermal degradation. Si O fractions left during POSS degradations were the key factor governing the formation of a gel network layer on the exterior surface. This layer possessed more compact structures, higher thermal stabilities, and some thermal insulation. In addition, percentage residues at 700°C (C₇₀₀) significantly increased from 10.8 to 15.5–22.8% in air. The storage modulus of two series of composites was slightly improved up to 90°C; furthermore, the temperature range of the rubbery state of them shifted to high temperature. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers