Effect of in situ surface‐modified nano‐SiO2 on the thermal and mechanical properties and crystallization behavior of nylon 1010

Nylon 1010 composites filled with two types of surface‐modified SiO₂ nanoparticles (RNS and DNS) were prepared by melt blending. The mechanical properties of the composites were evaluated. The influences of the surface‐modified nano‐SiO₂ on the thermal stability, crystallization behavior, and microstructure of nylon 1010 were investigated by thermogravimetric analysis, differential scanning calorimetry (DSC), X‐ray diffraction, and transmission electron microscopy. And the interfacial interactions between the fillers and polymer matrix were examined using a Fourier transformation infrared spectrometer. It was found that the addition of the surface‐modified nano‐SiO₂ had distinct influences on the thermal stability, mechanical properties, and crystallization behavior of nylon 1010. RNS and DNS as the fillers had different effects on the mechanical properties of nylon 1010. The composites filled with RNS at a mass fraction of 1–5% showed increased break elongation, Young's modulus, and impact strength but almost unchanged or even slightly lowered tensile strength than the unfilled matrix. The DNS‐filled nylon 1010 composites had obviously decreased tensile strength, whereas the incorporation of DNS also contributed to the increase in the Young's modulus of nylon 1010, but less effective than RNS. Moreover, the nylon 1010 composites had better thermal stability than the neat polymer matrix, and the composites filled with RNS were more thermally stable than those filled with DNS. The difference in the crystallinity of neat nylon 1010 and its composites filled with RNS and DNS was subtle, although the surface‐modified nano‐SiO₂ could induce or/and stabilize the γ‐crystalline formation of nylon 1010. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of functionalized nanosilica on properties of polyoxymethylene‐matrix nanocomposites

Amino group and methyl group functionalized nano‐silica (coded as RNS and DNS) particulates were separately used as nanofillers to prepare polyxymethylene‐matrix (denoted as POM‐matrix) nanocomposites by melt blending. The tensile strength, Young's modulus, and impact toughness of as‐prepared POM‐matrix nanocomposites were measured, and their thermal decomposition behavior and crystallization behavior were analyzed by means of thermogravimetric measurement and differential scanning calorimetry and polarized light microscope. Moreover, the morphology of as‐prepared POM‐matrix nanocomposites was observed with a transmission electron microscope. Results show that incorporating a proper content of RNS and DNS contributes to improve the tensile strength, Young's modulus and impact toughness of POM, and POM‐DNS nanocomposites with a high content of inorganic filler have better mechanical properties than POM‐RNS counterparts. Besides, POM‐matrix nanocomposites have a higher crystallization onset temperature and a smaller grain size than neat POM, which is due to the heterogeneous nucleation effect of DNS and RNS. Moreover, incorporating RNS containing surface amino group helps to increase the thermal stability of POM‐RNS nanocomposites and leads to an increase of initial decomposition temperature by about 27°C; but the introduction of DNS has little effect on the thermal decomposition behavior of POM. The reason lies in that RNS containing surface amino group can strongly chemically interact with thermal decomposed products of POM (it can absorb formaldehyde and formic acid generated via thermal decomposition of POM) but DNS with surface methyl group cannot absorb formaldehyde and formic acid. POLYM. COMPOS., 35:127–136, 2014. © 2013 Society of Plastics Engineers     

Interfacial structures and mechanical properties of PVC composites reinforced by CaCO3 with different particle sizes and surface treatments

The effects of particle size and surface treatment of CaCO₃ particles on the microstructure and mechanical properties of poly(vinyl chloride) (PVC) composites filled with CaCO₃ particles via a melt blending method were studied by SEM, an AG‐2000 universal material testing machine and an XJU‐2.75 Izod impact strength machine. The tensile and impact strengths of CaCO₃/PVC greatly increased with decreasing CaCO₃ particle size, which was attributed to increased interfacial contact area and enhanced interfacial adhesion between CaCO₃ particles and PVC matrix. Titanate‐treated nano‐CaCO₃/PVC composites had superior tensile and impact strengths to untreated or sodium‐stearate‐treated CaCO₃/PVC composites. The impact strength of titanate‐treated nano‐CaCO₃/PVC composites was 26.3 ± 1.1 kJ m⁻², more than three times that of pure PVC materials. The interfacial adhesion between CaCO₃ particles and PVC matrix was characterized by the interfacial interaction parameter B and the debonding angle θ, both of which were calculated from the tensile strength of CaCO₃/PVC composites. Copyright © 2005 Society of Chemical Industry     

Role of reactive compatibilization in preparation of nanosilica/polypropylene composites

The effect of reactive compatibilization on the mechanical properties of nanosilica filled polypropylene (PP) composites was studied in this work. First, the nanoparticles were grafted with poly(glycidyl methacrylate) (PGMA) by solution free‐radical polymerization, and then melt blended together with PP matrix and aminated PP (PP‐g‐NH₂) that acts as reactive compatibilizer. The reaction between epoxide groups of the grafted PGMA on the nanoparticles and amine groups of PP‐g‐NH₂ during compounding greatly improved interfacial interaction in the composites. As a result, tensile strength, Young's modulus, and notch impact strength of PP composites were increased at rather low filler content. The experimental results indicated that the reinforcing and toughening effects were controlled by flexibility of the grafted polymer as well as processing methods. POLYM. ENG. SCI., 47:499–509, 2007. © 2007 Society of Plastics Engineers.     

Physical and mechanical properties of Al(OH)3/polypropylene composites modified by in situ‐functionalized polypropylene

Al(OH)₃/polypropylene (PP) composites modified by in situ‐functionalized polypropylene (FPP) were prepared by a one‐step melt‐extrusion process. The effect of in situ FPP on the crystallization and melting behavior, melt‐flow index, limiting oxygen index, thermal degradation, mechanical properties, and fracture morphology of Al(OH)₃/PP composites was studied. Formation of in situ FPP resulted in a decreased crystallization temperature and melting point of PP in the composites, an increased melt‐flow index, and improved tensile and flexural strengths of Al(OH)₃/PP composites, whereas the thermal degradation behavior and limiting oxygen index was not been influenced. The impact strength of the Al(OH)₃/PP composites modified by in situ FPP depended upon the content of the initiator, dicumyl peroxide, and the monomer, acrylic acid. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2850–2857, 2002; DOI 10.1002/app.10269     

Surface treatment of phosphate glass fibers using 2‐hydroxyethyl methacrylate: Fabrication of poly(caprolactone)‐based composites

2‐Hydroxyethyl methacrylate (HEMA) solution (1–10 wt %) was prepared in methanol and phosphate glass fibers were immersed in that solution for 5 min before being cured (irradiation time: 30 min) under UV radiation. Maximum polymer loading (HEMA content) was found for the 5 wt % HEMA solution. Degradation tests of the fibers in aqueous medium at 37°C suggested that the degradation of the HEMA‐treated fibers was lower than that of the untreated fibers. X‐ray photoelectron spectroscopy revealed that HEMA was present on the surface of the fibers. Using 5 wt % HEMA‐treated fibers, poly(caprolactone) matrix unidirectional composites were fabricated by in situ polymerization and compression molding. For in situ polymerization, it was found that 5 wt % HEMA‐treated fiber‐based composites had higher bending strength (13.8% greater) and modulus (14.0% greater) than those of the control composites. For compression molded composites, the bending strength and modulus values for the HEMA‐treated samples were found to be 27.0 and 31.5% higher, respectively, than the control samples. The tensile strength, tensile modulus, and impact strength of the HEMA composites found significant improvement than that of the untreated composites. The composites were investigated by scanning electron microscopy after 6 weeks of degradation in water at 37°C. It was found that HEMA‐treated fibers inside the composite retained much of their original integrity while the control samples degraded significantly. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Morphology and mechanical properties of PVC/straw‐fiber coated with liquid nitrile‐butadiene rubber composites

This study exhibited an approach of high‐value utilization of straw fiber (SF) in polymer composites. The rigid poly(vinyl chloride) [PVC]/SF and PVC/SF coated with liquid nitrile‐butadiene rubber (PVC/LNBR‐SF) composites were both fabricated by melt mixing. The chemical structure and crystal structure of LNBR‐SF were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and X‐ray diffraction (XRD). The mechanical properties and micro‐structure of PVC/SF and PVC/LNBR‐SF composites were also studied. FTIR and XRD results showed that the chemical structure and crystal structure of SF did not change after modifying with LNBR. The mechanical properties analysis showed that the PVC/LNBR‐SF composites exhibited better tensile strength, elongation at break and notched impact strength than those of PVC/SF composites owing to the compatibilization and toughening effect of LNBR. Scanning electron microscope results indicated that the LNBR improved the dispersion of SF in PVC matrix to some extent. The interface adhesion between SF and PVC matrix with adding LNBR was also enhanced. These results suggested that PVC/LNBR‐SF composites exhibited promising potential for practical application in substitute for wood. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44119.     

PMMA‐grafted‐silica/PVC nanocomposites: Mechanical performance and barrier properties

Poly(vinyl chloride) (PVC)/SiO₂ nanocomposites were prepared via melt mixture using a twin‐screw mixing method. To improve the dispersion degree of the nanoparticles and endow the compatibility between polymeric matrix and nanosilica, SiO₂ surface was grafted with polymethyl methacrylate (PMMA). The interfacial adhesion was enhanced with filling the resulting PMMA‐grafted‐SiO₂ hybrid nanoparticles characterized by scanning electron microscopy. Both storage modulus and glass transition temperature of prepared nanocomposites measured by dynamic mechanical thermal analysis were increased compared with untreated nanosilica‐treated PVC composite. A much more efficient transfer of stresses was permitted from the polymer matrix to the hybrid silica nanoparticles. The filling of the hybrid nanoparticles caused the improved mechanical properties (tensile strength, notched impact strength, and rigidity) when the filler content was not more than 3 wt %. Permeability rates of O₂ and H₂O through films of PMMA‐grafted‐SiO₂/PVC were also measured. Lower rates were observed when compared with that of neat PVC. This was attributed to the more tortuous path which must be covered by the gas molecules, since SiO₂ nanoparticles are considered impenetrable by gas molecules. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effect of cenosphere surface treatment and blending method on the tensile properties of thermoplastic matrix syntactic foams

The influence of cenosphere surface treatment and blending method on the properties of injection molded high‐density polyethylene (HDPE) matrix syntactic foams is investigated. Cenospheres are treated with silane and HDPE is functionalized with dibutyl maleate. Tensile test specimens are cast with 20, 40, and 60 wt % of cenospheres using injection molding. Modulus and strength are found to increase with increasing cenosphere content for composites with treated constituents. Highest modulus and strength were observed for 40 and 60 wt % untreated mechanically mixed and treated brabender mixed cenospheres/HDPE blends, respectively. These values are 37 and 17% higher than those for virgin and functionalized HDPE. Theoretical models are used to assess the effect of particle properties and interfacial bonding on modulus and strength of syntactic foams. Brabender mixing method provided highest ultimate tensile and fracture strengths, which is attributed to the effectiveness of Brabender in breaking particle clusters and generating the higher particle–matrix surface area compared to that by mechanical mixing method. Theoretical trends show clear benefits of improved particle–matrix interfacial bonding in the strength results. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43881.     

Mechanical properties of talc‐ and (calcium carbonate)‐filled poly(vinyl chloride) hybrid composites

The main objective of this study was to investigate and compare the mechanical properties of poly(vinyl chloride) (PVC) composites filled with calcium carbonate (CaCO₃), talc, and talc/CaCO₃. Talc and CaCO₃ with different grades were incorporated into the PVC matrix. To produce the composites, the PVC resin, fillers, and other additives were first dry‐blended by using a laboratory mixer before being milled into sheets in a two‐roll mill. Test specimens were prepared by compression molding, after which the mechanical properties of the composites were determined. Single and hybrid filler loadings used were fixed at 30 phr (parts per hundred parts of resin). Talc‐filled composite showed the highest flexural modulus and the lowest impact strength, whereas uncoated, ground, 1‐μm CaCO₃ (SM 90) showed optimum properties in terms of impact strength and flexural modulus among all grades of CaCO₃. It was selected to combine with talc at different ratios in the hybrid composites. The impact strength of the hybrid composites gradually increased with increasing SM 90 content, but the flexural and tensile properties showed an opposite behavior. Hybrid (10 phr talc):(20 phr SM 90)‐filled PVC composite reached a synergistic hybridization with balanced properties in impact strength, as well as flexural and tensile properties. J. VINYL ADDIT. TECHNOL., 2012. © 2012 Society of Plastics Engineers     

Effects of nanosilica filler surface modification and compatibilization on the mechanical,thermal and microstructure of PP/EPR blends

Polypropylene/ethylene-propylene rubber/nanosilica (PP/EPR/nano-SiO₂) composites were prepared by a melt blending masterbatch process using a Brabender mixer. In order to improve the interfacial adhesion and achieve diverse desired properties of the composites, nanosilica surface silylation by means of two silane coupling agents: N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (AEAPTMS) and 3-methacryloxypropyltrimethoxysilane (MPTMS) was explored. The composites were also compatibilized using three compatibilizers: methyl methacrylate grafted PP (MMA-g-PP), glycidylmethacrylate grafted PP (GMA-g-PP) and maleic anhydride grafted PP (MAH-g-PP). The properties of the blends and the composites were examined using tensile and Izod impact tests, differential scanning calorimetry (DSC), thermogravimetric analysis (ATG) and scanning electron microscopy (SEM). According to the mechanical property evaluations, the incorporation of nano-SiO₂ particles into PP/EPR blend improved the tensile strength and Young’s modulus of the composites. The elongation and Izod impact strength were adversely affected. A significant improvement in the mechanical properties was obtained for the composites with AEAPTMS-SiO₂ and MAH-g-PP. The DSC results indicated that the incorporation of the modified silica and MAH-g-PP increased the crystallinity of the composites. However, no significant variation in the crystallinity was observed as a result of the addition of MMA-g-PP and GMA-g-PP. The TGA results revealed that the composites exhibit a higher thermal stability than that of the neat matrix. SEM micrographs of the fractured surfaces revealed a two-phase morphology with EPR nodules being dispersed in the PP matrix. SEM also indicated that the incorporation of MAH-g-PP into PP/EPR composites contributes to a better dispersion of the EPR phase and nano-SiO₂ particles in the polymer matrix.     

Study on poly(butylene adipate‐co‐terephthalate)/starch composites with polymeric methylenediphenyl diisocyanate

To lower the cost of poly(butylene adipate‐co‐terephthalate) or PBAT, starch was used as a filler in this study. To increase tensile strength of PBAT/starch composites, polymeric methylenediphenyl diisocyanate (pMDI) was used as a compatibilizer. PBAT was melt‐mixed with starch in a kneader, and then the mixtures were compression‐molded. The effects of starch and pMDI content on the tensile strength and elongation at break of PBAT/starch composites were examined. The morphology and biodegradability of the composites in soil were also studied. The tensile strength of PBAT and PBAT/starch composites increases with increasing content of pMDI. The increase of weight average molecular weight of PBAT and improved interaction between PBAT and starch were observed with increasing content of pMDI. The weight average molecular weights of buried PBAT and the composites in soil significantly decrease. Especially, the reduction of the weight average molecular weight of PBAT/starch (70/30) composite is the most significant. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41884.     

A study on the properties of PC/LCP/MWCNT with and without compatibilizers

Recent study deals with the effect of functionalized Muti-walled carbon nanotube (MWCNT) and other compatibilizers (Closite 6A and Zn⁺⁺ ion coated nanosilica) on the compatibility and properties of polycarbonate (PC) and Liquid Crystalline Polymer (LCP). The nanocomposites have been melt blended using twin-screw extruder and molded in a compression mold. A remarkable enhancement of thermal, dynamic mechanical properties have been observed with the incorporation of functionalized MWCNT and compatibilizers. Zn⁺⁺ ion coated nanosilica seems to be more effective as compatibilizer incase of the concerned system. Percent crystallinty associated with the crystallite size have also been increased due to the heterogeneous nucleation of the functionalized MWCNT and compatibilizers. Compatibility between PC and LCP has been studied in terms of particle size determined by Scion Image Analysis in Field Emission Scanning Electron Microscopic (FESEM) study. Dispersion of MWCNT has been exhibited by High Resolution Transmission Electron Microscope (HRTEM).     

Nanocomposites of poly[(butylene succinate)‐co‐(butylene adipate)] (PBSA) and twice‐functionalized organoclay

A new method is described to prepare composites of poly[(butylene succinate)‐co‐(butylene adipate)] (PBSA) with an organophilic clay having a particular functional group, namely twice‐functionalized organoclay (TFC). TFCs were produced by treating Cloisite 25A^® with (glycidyloxypropyl)trimethoxy silane (GPS) or (methacryloyloxypropyl)trimethoxy silane (MPS). Reaction of the silane compound with the organoclay surface was monitored by Fourier‐transform infrared spectroscopy (FTIR). PBSA composites with the three different clays were prepared successfully via melt mixing. The d spacing and the morphology of the composites were monitored by X‐ray diffraction and by transmission electron microscopy. The linear storage modulus of the composites in the melt state increased significantly as a result of incorporation of TFC. Tensile modulus and strength at break of PBSA/TFC–GPS and those of PBSA/TFC–MPS were far superior to those of PBSA/C25A. Copyright © 2005 Society of Chemical Industry     

Mechanical properties of high density packed silica/poly(vinyl chloride) composites

This article focuses on the preparation and mechanical properties of silica/poly(vinyl chloride) (PVC) composites enriched with 60% mass ratio of 130 nm and 30 nm silica sphere fillers. Silica particles were pre‐treated with silane, IO₇ T₇(OH)₃ (trisilanol isooctyl polyhedral‐oligomeric silsesquioxane) to prevent agglomeration. The dispersion and interfacial compatibility of silica particles in a PVC matrix were investigated by scanning electron microscopy. The composite mechanical properties were characterized by tensile test, revealing improved Young modulus and tensile strength. Compared to pure PVC, the stiffness of 30 nm and 130 nm silica/PVC composites is on average increased by 30–40%, respectively. Similar trend was observed for the composite tensile strength on the change of the silica size. In contrast, elongation at break decreased for both composites compared to pure PVC, for 15% in 30 nm and for 30% in 130 nm silica/PVC composite. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Characterization and properties of activated nanosilica/polypropylene composites with coupling agents

In this work, nanosilica/polypropylene composites containing 1 wt% of silica nanoparticles were prepared by melt mixing in a Thermo Haake internal mixer. Prior compounding, nanosilica was subjected to surface activation using sodium hydroxide (NaOH) solution. The effectiveness of the activation process was evaluated by measuring the amount of hydroxyl groups ( OH) on the surface of nanosilica via titration method and supported by FTIR analysis. Two coupling agents namely 3‐aminopropyl triethoxysilane (APTES) and neopentyl (diallyl)oxy, tri(dioctyl) phosphate titanate (Lica 12) were used for surface treatment after activation process. The mechanical properties of polypropylene matrix reinforced with silica nanoparticles were determined by tensile and impact test. Hydroxyl groups on the nanosilica surface played an important role in enhancing the treatment with silane coupling agents. To increase the amount of hydroxyl groups on the nanosilica surface, the optimum concentration of NaOH is 1 mol%. Tensile strength, tensile modulus, and impact strength of nanosilica/PP composites improved with activation process. As the coupling agent is concerned, APTES coupling agent is more pronounced in enhancing the mechanical properties of the composites when compared with Lica 12 coupling agent. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

PVC／蒙脱土复合材料的制备与结构研究

采用钠基蒙脱土及经有机化处理后的蒙脱土分别通过纳米粒子直接填充分散法和熔融插层法与PVC混合制备PVC/蒙脱土纳米复合材料。对有机蒙脱土的结构进行了表征；对上述两类纳米复合材料的结构及力学性能进行了研究。此外，考察了采用硅烷偶联剂KH570处理钠基蒙脱土后与PVC熔融混合制备的纳米复合材料的力学性能。结果表明，经硅烷偶联剂处理后，纳米复合材料的拉伸强度和冲击强度均有明显的提高。     

Effects of PBO fiber and clay on the mechanical,morphological, and dynamic mechanical properties of NR/HDPE blends

Poly(p‐phenylene‐2,6‐benzobisoksazole) (PBO) and natural rubber (NR)/high density polyethylene (HDPE) composites were melt‐blended in a Haake internal mixer. The tensile strength, tensile modulus, and impact strength increased with fiber loading and optimized at 20%. Incorporation of clay into the NR/HDPE/PBO composites resulted in an improvement of tensile strength for NR/HDPE/PBO composites compared to the systems without clay. However, addition of clay was only effective at low contents (5–7.5%). Additional improvement of tensile strength, tensile modulus, and impact strength of the hybrid composite was observed on addition of liquid natural rubber (LNR). Scanning electron micrographs of the samples had indicated that the presence of clay decreased the domain size of the dispersed phase. Results on dynamic response showed that incorporation of clay and LNR into the composites had increased the storage modulus and reduced the tan δ. The shift of glass transition temperature (T_g) to higher values for composites also indicated good interaction between the fiber and the matrix. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers.     

纳米二氧化硅颗粒表面设计及其填充聚氯乙烯复合材料的性能

利用表面原位接枝聚合在纳米二氧化硅颗粒表面引入聚甲基丙烯酸甲酯(PMMA)高分子链段,用共混法制备了nano-SiO2/PVC复合材料,研究了不同界面特性时SiO2/PVC复合材料的力学性能.研究结果表明通过表面原位接枝聚合反应可以在纳米二氧化硅颗粒表面接枝聚甲基丙烯酸甲酯;表面接枝PMMA的nano-SiO2/PVC复合材料在力学和加工性能等方面都优于偶联剂处理和表面未处理样品.在纳米二氧化硅颗粒填充量为0%～8%(wt)时,复合材料的拉伸强度和冲击强度随着填充量的提高先上升后下降,并在4%～6%(wt)达到最大值.经PMMA表面接枝后SiO2/PVC具有更强的界面作用,偶联剂KH570处理的次之,表面未处理样品的最差.     

A novel method of hyperbranched poly(amide‐ester) modifying nano‐SiO2 and study of mechanical properties of PVC/nano‐SiO2 composites

A new method of surface chemical modification of nano‐SiO₂ was proposed in the paper. In the presence of catalyst, the active hydroxyl groups on the surface of nano‐SiO₂ reacted with AB₂‐type monomer (N,N‐dihydroxyethyl‐3‐amino methyl propionate) by one‐step polycondensation. And the product's Fourier transform infrared graphs and transmission electron microscopy (TEM) images proved that hyperbranched poly(amine‐ester) (HPAE) was grafted from nano‐SiO₂ surface successfully. Moreover, polyvinyl chloride (PVC)/modified nano‐SiO₂ composites were made by melt‐blending. The composites' structures and mechanical properties were characterized by TEM, scanning electron microscopy, and electronic universal testing machine. The results showed that nano‐SiO₂ grafted by HPAE increased obviously in dispersion in PVC matrix, and mechanical properties of PVC were effectively improved. Additionally, it was found that mechanical properties of PVC/nano‐SiO₂ composites reached the best when weight percent of nano‐SiO₂ in PVC matrix was 1%. Compared with crude PVC, the tensile strength of HPAE grafted nano‐SiO₂/PVC composite increased by 24.68% and its break elongation, flexural strength, and impact strength increased by 15.73, 4.07, and 184.84%, respectively. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers