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1.
Clay containing polypropylene (PP) nanocomposites were prepared by direct melt mixing in a twin screw extruder using different types of organo‐modified montmorillonite (Cloisite 15 and Cloisite 20) and two masterbatch products, one based on pre‐exfoliated clays (Nanofil SE 3000) and another one based on clay–polyolefin resin (Nanomax‐PP). Maleic anhydride‐grafted polypropylene (PP‐g‐MA) was used as a coupling agent to improve the dispersability of organo‐modified clays. The effect of clay type and clay–masterbatch product on the clay exfoliation and nanocomposite properties was investigated. The effect of PP‐g‐MA concentration was also considered. Composite morphologies were characterized by X‐ray diffraction (XRD), field emission gun scanning electron microscopy (FEG‐SEM), and transmission electron microscopy (TEM). The degree of dispersion of organo‐modified clay increased with the PP‐g‐MA content. The thermal and mechanical properties were not affected by organo‐modified clay type, although the masterbatch products did have a significant influence on thermal and mechanical properties of nanocomposites. Intercalation/exfoliation was not achieved in the Nanofil SE 3000 composite. This masterbatch product has intercalants, whose initial decomposition temperature is lower than the processing temperature (T ~ 180°C), indicating that their stability decreased during the process. The Nanomax‐PP composite showed higher thermal and flexural properties than pure PP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

2.
Preparation and morphology of Polyamide 6 (PA6)/high density polyethylene (HDPE)/Styrene/Ethylene–Butylene/Styrene grafted with maleic anhydride (SEBS‐g‐MA)/Modified clay nanocomposites were studied. Mixing was performed using melting process in an extruder co‐rotating twin screw. After etching the materials with boiling toluene and THF at room temperature, the morphology of sample checked by scanning electron microscopy (SEM) analyses. X‐ray diffraction (XRD) used for evaluation of the effects of organo‐clay addition in the structure of nanocomposites. XRD traces showed that the characteristic (001) peak of the nanocomposites shifted to the lower degree region. XRD and SEM results showed more uniformly distribution and dispersion of HDPE in the PA6 matrix. Better sample morphology obtained, regarding less distance, and more uniformity between nanoparticles. The mechanical properties like tensile strength, impact strength, hardness and thermal properties of these toughened nanocomposites are discussed in terms of the nanoclay, SEBS‐g‐MA contents and morphology. Adding nanoclay improved hardness of nanocomposites product but reduced toughness and thermal properties. Meanwhile the presence of SEBS‐g‐MA as a compatibilizer improved toughness, thermal properties, hardness property, and the balance properties are achieved. POLYM. ENG. SCI., 55:29–33, 2015. © 2014 Society of Plastics Engineers  相似文献   

3.
This report deals with the development of unmodified and modified halloysite nanotube (HNT) based cyclic olefin copolymer (COC) composites. Maleic anhydride grafted polyethylene (MA‐g‐PE) has been used as a compatibilizer. Exfoliation of organically modified HNTs (mHNTs) and dispersion of it in polymer matrix was observed by X‐ray diffraction, transmission electron microscopy, and field emission scanning electron microscopy analysis, respectively. Augmented dynamic mechanical and thermal properties of the composites were provided by incorporating mHNTs into the pure matrix. In this work, we have proposed that the modification of HNTs enhanced the dispersion and strong interfacial interaction which led to better performance of the composites where MA‐g‐PE acts as a bridging tool between polar clays and nonpolar COC. POLYM. COMPOS., 36:955–960, 2015. © 2014 Society of Plastics Engineers  相似文献   

4.
Potato peel powder (POPL), which is biodegradable, has been used as filler material in polypropylene (PP) matrix in varying concentration from 10 to 40% by weight to prepare biocomposites and investigated water absorption, physicomechanical and thermal properties. Scanning electron microscopy and X‐ray diffraction has been used for morphological characterization and crystallization studies. Flexural modulus of biocomposites increased by 40% compared with neat PP at 30% loading of POPL. Flexural strength also increased with increasing filler loading. Tensile strength of biocomposites has been observed to be comparable with neat PP up to 20% filler loading and increase in tensile modulus up to 40% was seen in biocomposites with 20% filler loading. Impact strength of biocomposites up to 20% filler loading was found to be at par with neat PP. Use of MA‐g‐PP compatibilizer in the biocomposites yielded better physico‐mechanical and thermal properties than biocomposites without compatibilizer. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42445.  相似文献   

5.
2,7‐Bis(4‐aminophenoxy) naphthalene (BAPN), a naphthalene‐containing diamine, was synthesized and polymerized with a 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride (BTDA) to obtain a polyimide (PI) via thermal imidization. To enhance the thermal and mechanical properties of the polymer, PI–Montmorillonite (MMT) nanocomposites were prepared from a DMAc solution of poly(amic acid) and a DMAc dispersion of MMT, which were organo‐modified with various amounts of n‐dodecylamine (DOA) or cetylpyridium chloride (CPC). FTIR, XRD, and TEM (transmission electron microscopy) were used to verify the incorporation of the modifying agents into the clay structure and the intercalation of the organoclay into the PI matrix. Results demonstrated that the introduction of a small amount of MMT (up to 5%) led to the improvement in thermal stability and mechanical properties of PI. The decomposition temperature of 5% weight loss (Td,5%) in N2 was increased by 46 and 36°C in comparison with pristine PI for the organoclay content of 5% with DOA and CPC, respectively. The nanocomposites were simultaneously strengthened and toughened. The dielectric constant, CTE, and water absorption were decreased. However, at higher organoclay contents (5–10%), these properties were reduced because the organoclay was poorly dispersed and resulted in aggregate formation. The effects of different organo‐modifiers on the properties of PI–MMT nanocomposite were also studied; the results showed that DOA was comparable with CPC. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci, 2006  相似文献   

6.
Chitosan–clay biocomposites have been prepared in which KSF‐montmorillonite (KSF) is used as filler and diluted acetic acid is used as solvent for dissolving and dispersing chitosan and montmorillonite, respectively. The effect of KSF loadings in biocomposites has been investigated. The characterization with different methods (FTIR, DSC, TGA, SEM, and XRD) on chitosan/KSF biocomposites systems was examined. Morphology and properties of chitosan biocomposites have been studied compared with those of pure chitosan. The FTIR and SEM results indicated the formation of an intercalated‐and‐exfoliated structure at low KSF content and an intercalated‐and‐flocculated structure at high KSF content. The thermal stability and the mechanical properties of the composites were also examined by DSC, TGA/DTG, and tensile strength measurements, respectively. The dispersed clay improves the thermal stability of the matrix systematically with the increase of clay loading. Tensile strength of a chitosan film was enhanced until the clay ratio up to 2 wt% and elongation‐at break decreased with addition of clay into the chitosan matrix. The XRD results confirmed the intercalation of the biopolymer in the clay interlayer by the decrease of 2θ values while the chitosan–clayratio increases. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers  相似文献   

7.
Unsaturated polyester (UP) systems give rise to numerous possible approaches in synthesizing nanocomposites. A simultaneous mixing method was used to synthesize UP‐resin/organo‐clay nanocomposites. The effects of various mixing processes, using several organically‐modified clay types, were investigated. The incorporation of these organo‐clays resulted in an intercalated structure, the extent of which depended mainly on the type of the clay organic treatment. Organo‐clays that exhibited the highest intercalation levels were further studied using a sequential mixing method. The UP‐alkyd (without styrene) was mixed with different organo‐clays. Processing parameters such as mixing modes, applied shearing levels, clay contents, and mixing‐temperatures were investigated. Prolonged high shear levels promoted the intercalation and exfoliation of the silicate layers, resulting in a better dispersion of clay particles. The high shear levels effects were achieved by vigorous mechanical mixing and were intensified by using large amounts of clay and optimized matrix viscosity. Rheological studies of the nanocomposites were found complementary and in correlation with morphological and thermal characterization. This methodological approach provides a basis for understanding the structuring processes involving the formation of the UP/clay nanocomposites and establishing materials‐processing‐structure interrelations. Polym. Eng. Sci. 45:174–186, 2005. © 2005 Society of Plastics Engineers.  相似文献   

8.
A trifunctional organo alkoxysilane (3‐aminopropyl)triethoxysilane (γ‐APS) has been used as reagent for the chemical modification of montmorillonite clay. Silane grafting was taken place in dry and hydrolyzing conditions. Silane grafted and pristine clay took part in interfacial polycondensation process to deposit a layer of nylon‐66 onto the clay lamellae and therefore, enhance their affinity with nylon‐66 matrix. Evidence of presence of grafted silane molecules and deposition of nylon‐66 on clay particles were provided by Fourier transform‐infrared, thermogravimetric analysis (TGA), and X‐ray diffraction (XRD). Such modified clays and pristine clays were melt compounded with nylon‐66. The structures of the resulting nylon composites were characterized using XRD and transmission electron microscopy and the results showed presence of both intercalation and exfoliation. TGA thermograms of nanocomposites indicated improved thermal stability upon the incorporation of silane grafted montmorillonite. Furthermore, differential scanning calorimetry scans showed that silane modified clays promoted crystallization in nanocomposites. Increase of storage modulus and depression of tan δ peak in nanocomposites in dynamical mechanical thermal analysis were observed. The rheological properties of nylon‐66 and nanocomposites were also evaluated and differences in values of complex viscosity of samples were noticed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

9.
The oligomeric poly(styrene‐acrylamide‐vinylbenzylchloride) (P(St‐AM‐VBC)) quaternary ammonium salts have been prepared from the reactions of trimethylamine with the corresponding P(St‐AM‐VBC)s, which were synthesized by free‐radical polymerization of a mixture of styrene, acrylamide, and vinylbenzylchloride. Then the swelling tunable oligomeric poly(styrene‐co‐acrylamide) modified clays have been prepared through cation exchange of the sodium ions in the clay with the corresponding P(St‐AM‐VBC) quaternary ammonium salts. The P(St‐AM‐VBC) and its modified clays have been characterized by infrared spectra (IR), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), proton nuclear magnetic resonance (1H NMR), X‐ray diffraction (XRD), and transmission electron microscopy (TEM). The solvent‐swelling capacity of poly(styrene‐co‐acrylamide) modified clays have also been tested, and the experimental results have indicated that these clays are novel swelling tunable organic clays. XRD and TEM studies have shown that these novel swelling tunable clays are well‐intercalated or exfoliated. Furthermore, TGA analysis shows that these polymerically modified clays have high thermal stability for nanocomposites by melt blending. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008  相似文献   

10.
Nanocomposites of poly(methyl methacrylate) (PMMA) filled with 3 wt% of modified natural Algerian clay (AC; montmorillonite type) were prepared by either in situ polymerization of methyl methacrylate initiated by 2,2′‐azobisisobutyronitrile or a melt‐mixing process with preformed PMMA via twin‐screw extrusion. The organo‐modification of the AC montmorillonite was achieved by ion exchange of Na+ with octadecyldimethylhydroxyethylammonium bromide. Up to now, this AC montmorillonite has found applications only in the petroleum industry as a rheological additive for drilling muds and in water purification processes; its use as reinforcement in polymer matrices has not been reported yet. The modified clay was characterized using X‐ray diffraction (XRD), which showed an important shift of the interlayer spacing after organo‐modification. The degree of dispersion of the clay in the polymer matrix and the resulting morphology of nanocomposites were evaluated using XRD and transmission electron microscopy. The resulting intercalated PMMA nanocomposites were analysed using thermogravimetric analysis and differential scanning calorimetry. The glass transition temperature of the nanocomposites was not significantly influenced by the presence of the modified clay while the thermal stability was considerably improved compared to unfilled PMMA. This Algerian natural montmorillonite can serve as reinforcing nanofiller for polymer matrices and is of real interest for the fabrication of nanocomposite materials with improved properties. Copyright © 2009 Society of Chemical Industry  相似文献   

11.
《Polymer Composites》2017,38(2):363-370
Porous chitosan/graphene oxide (CHT/GO) biocomposites with 0.5, 1, 2, and 3 wt% GO were prepared by freeze‐drying method. The biocomposites were characterized regarding structural, morphological, and thermal properties, degradation, and swelling responses. Raman spectroscopy and scanning electron microscopy (SEM) results indicated good GO dispersion within the polymer host and highly porous structure for the obtained biocomposites. The GO presence has a profound effect on the structural features of the biocomposites generating decrease of swelling degree and enzymatic biodegradation rate. Conversely, the thermal stability of the biocomposites was significantly improved, and the decomposition temperature at which the mass loss is 3% (T d,3%) was increased with 64°C by adding 3 wt% GO within the CHT. The ability of the biocomposites to form apatite‐like crystals was also investigated. X‐ray diffraction and SEM analyses indicated the formation of apatite deposits on the CHT/GO biocomposites. POLYM. COMPOS., 38:363–370, 2017. © 2015 Society of Plastics Engineers  相似文献   

12.
Ethyl vinyl acetate (EVA) copolymers are potential materials for biomedical applications due to their exceptional mechanical properties and biocompatibility. As new medical device designs continue to reduce in size, new materials are required that exhibit improved strength and toughness. In this research, EVA nanocomposites containing synthetic montmorillonite (MMT) are being investigated as new biomedical materials with similar flexibility, biocompatibility, and biostability to neat EVA, but with far superior tensile strength and toughness. We show that the pre‐dispersing of the organo‐MMT prior to melt compounding with the EVA matrix can facilitate nanofiller exfoliation and dispersion in the EVA, thereby enabling significant improvement of EVA nanocomposite performance when high organo‐MMT loading (5 wt %) was added. It was observed that the polarity of pre‐dispersing medium influenced the nanofiller's surfactant organization and distribution, organo‐MMT exfoliation, and dispersion in the EVA, and also interphases of the host copolymer. Consequently, changes in morphology have brought noticeable effects on the mechanical and thermal properties of the EVA. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43204.  相似文献   

13.
Natural rubber/cis‐1,4‐polybutadiene (NR/BR) blends with two types of layered nanofillers, montmorillonite (MMT) and layered double hydroxide (LDH), both in pristine and organically modified forms are produced and investigated. Faster curing is found for all the NR/BR blends, except for the one containing the unmodified MMT. This effect can be attributed to the groups placed in the interlayer regions of the clays; more precisely to ammonium groups for the organo‐MMTs and to ? OH groups for LDHs. Mechanical properties and thermal stability of rubber compounds are investigated. It has been demonstrated that the performance of the final nanocomposite is significantly affected by the kind of clay. Particularly, the organo‐MMTs provoke an improvement of the mechanical properties and increase the thermal stability of about 4–5° C in respect to the pure NR/BR matrix. On the contrary, the poor compatibility of unmodified MMT and of LDH clays with the rubber blend is evident and no enhancement on the composite performance has been observed. POLYM. ENG. SCI., 2013. © Society of Plastics Engineers  相似文献   

14.
To improve the thermal and mechanical properties of liquid silicone rubber (LSR) for application, the graphene oxide (GO) was proposed to reinforce the LSR. The GO was functionalized with triethoxyvinylsilane (TEVS) by dehydration reaction to improve the dispersion and compatibility in the matrix. The structure of the functionalized graphene oxide (TEVS‐GO) was evaluated by Thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectra, X‐ray diffraction (XRD), and energy dispersive X‐ray spectroscopy (EDX). It was found that the TEVS was successfully grafted on the surface of GO. The TEVS‐GO/LSR composites were prepared via in situ polymerization. The structure of the composites was verified by FTIR, XRD, and scanning electron microscopy (SEM). The thermal properties of the composites were characterized by TGA and thermal conductivity. The results showed that the 10% weight loss temperature (T10) increased 16.0°C with only 0.3 wt % addition of TEVS‐GO and the thermal conductivity possessed a two‐fold increase, compared to the pure LSR. Furthermore, the mechanical properties were studied and results revealed that the TEVS‐GO/LSR composites with 0.3 wt % TEVS‐GO displayed a 2.3‐fold increase in tensile strength, a 2.79‐fold enhancement in tear strength, and a 1.97‐fold reinforcement in shear strength compared with the neat LSR. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42582.  相似文献   

15.
Unsaturated polyester (UP) toughened nanocomposites were prepared using both sisal fibers and montmorillonite clays. The effect of fibers and Cloisite 30B (C30B) nanoclays on the mechanical properties, thermal stability, flame retardant, and morphological behavior of the UP toughened epoxy (Epoxy/UP) were systematically studied. The chemical structures of Epoxy, UP, and Epoxy/UP systems were characterized using Proton Nuclear magnetic resonance (1HNMR) and Fourier transform infrared (FTIR) spectra. The homogeneous dispersion of nanoclay within the polymer matrix was analyzed using transmission electron microscopy (TEM) and X‐ray diffraction (XRD) analysis. Incorporation of sisal fibers and C30B nanoclays within Epoxy/UP system resulted in an increase in the mechanical, thermal, and flame retardance properties. Thermogravimetric analysis (TGA) has been employed to evaluate the thermal degradation kinetic parameters of the composites using Kissinger and Flynn‐Wall‐Ozawa methods. Cone calorimeter, UL‐94, and LOI tests revealed a reduction in the burning rate of the matrix with the addition of fibers and nanoclays. The results showed that the treated fiber reinforced nanocomposites had higher thermal stability and better flame retardant properties than the treated fiber reinforced composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42068.  相似文献   

16.
Nanocomposites based on biodegradable poly(?‐caprolactone) (PCL) and layered silicates (montmorillonite, MMT) were prepared either by melt interaction with PCL or by in situ ring‐opening polymerization of ?‐caprolactone as promoted by the so‐called coordination‐insertion mechanism. Both non‐modified clays (Na+ ‐MMT) and silicates modified by various alkylammonium cations were studied. Mechanical and thermal properties were examined by tensile testing and thermogravimetric analysis. Even at a filler content as low as 3 wt% of inorganic layered silicate, the PCL‐layered silicate nanocomposites exhibited improved mechanical properties (higher Young's modulus) and increased thermal stability as well as enhanced flame retardant characteristics as a result of a charring effect. It was shown that the formation of PCL‐based nanocomposites depended not only on the nature of the ammonium cation and related functionality but also on the selected synthetic route, melt intercalation vs. in situ intercalative polymerization. Interestingly enough, when the intercalative polymerization of ?‐caprolactone was carried out in the presence of MMT organo‐modified with ammonium cations bearing hydroxyl functions, nanocomposites with much improved mechanical properties were recovered. Those hybrid polyester layered silicate nanocomposites were characterized by a covalent bonding between the polyester chains and the clay organo‐surface as a result of the polymerization mechanism, which was actually initiated from the surface hydroxyl functions adequately activated by selected tin (II) or tin (IV) catalysts.  相似文献   

17.
A series of poly(butylene succinate) (PBS) containing organo‐modified layered double hydroxide (LDH) are prepared by melt compounding and by in situ polymerization of succinic ester and 1,4‐butanediol. Various LDHs intercalated with renewable organic anions are used. More specifically, lauryl sulfate, stearate, succinate, adipate, sebacate, citrate, and ricinoleate ions are used as LDHs organo‐modifiers. The thermal, rheological, and dynamic mechanical properties of the samples are investigated. The results reveal a general mechanical reinforcement imparted by the clays. Significant changes are observed for the in situ polymerized nanocomposites, especially for LDH stearate which improves the properties of PBS nanostructure, whereas very few differences are observed for the other samples. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1931–1940, 2013  相似文献   

18.
《Polymer Composites》2017,38(12):2852-2862
Coconut shell fiber‐reinforced polypropylene (PP/CSP) biocomposites were prepared by using hand lay‐out technique with different fractions of the modified fibers. Before proceeding to fabrication method, fibers were made compatible by chemical modification with acrylic acid. The interaction of acrylic modified coconut shell fibers with PP matrix was studied by using Fourier transforms Infrared spectroscopy. The morphology of chemically modified coconut fibers and coconut shell fibers reinforced polypropylene biocomposites were studied by using field emission scanning electron microscope. Due to strong interfacial interaction between PP and CSP, mechanical properties were improved. It was found that the tensile strength, elongation at break and loss modulus, rigidity of PP bio‐composites were investigated as compared with that of virgin PP matrix. The thermal properties of the fabricated biocomposites were investigated by using thermogravimetric analysis. The semi‐ductile properties of the fabricated PP biohybrids were confirmed through erosion ring test. POLYM. COMPOS., 38:2852–2862, 2017. © 2015 Society of Plastics Engineers  相似文献   

19.
Seaweed waste (SWW) is a residue or by‐product from the filtration step of the agar extraction process, and it has been explored as an inexpensive and effective filler for incorporation by melt blending into a poly(lactic acid) (PLA) matrix. PLA‐SWW biocomposites were manufactured with various contents of SWW (0, 5, 10, 15, and 20 wt %) using a sheet extrusion process. PLA was functionalized with maleic anhydride (MAH) by reactive extrusion using dicumyl peroxide (DCP) as an initiator, and it was extruded using 0, 5, and 20 wt %. SWW content. The mechanical, thermal, structural, and morphological properties of the processed biocomposites were investigated. Regarding the mechanical behavior, a slight increase in the tensile modulus was observed at low SWW content. The thermal properties indicated that the rigid amorphous phase content was enhanced in the biocomposites. This work suggests that SWW can be used as filler to develop environmental friendly biocomposites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42320.  相似文献   

20.
Nanocomposites based on blends of poly(butylene succinate) (PBS) and thermoplastic cassava starch (TPS) were prepared using a two‐roll mill and compression molding, respectively. Two different types of clay, namely sodium montmorillonite (CloisiteNa) and the organo‐modified MMT (Cloisite30B) were used. The morphological and mechanical properties of the nanocomposite materials were determined by using XRD technique and a tensile test, respectively. Thermal properties of the composite were also examined by dynamic mechanical thermal analysis and thermal gravimetric techniques. Barrier properties of the nanocomposites were determined using oxygen transmission rate (OTR) and water vapor transmission rate (WVTR) tests. From the results, it was found that by adding 5 pph of the clay, the tensile modulus and the thermal properties of the blend containing high TPS (75 wt %) changed significantly. The effects were also dependent on the type of clay used. The use of Cloisite30B led to a nanocomposite with a higher tensile modulus value, whereas the use of CloisiteNa slightly enhanced the thermal stability of the material. OTR and WVTR values of the blend composites containing high PBS ratio (75 wt %) also decreased when compared to those of the neat PBS/TPS blend. XRD patterns of the nanocomposites suggested some intercalation and exfoliation of the clays in the polymer matrix. The above effects are discussed in the light of different interaction between clays and the polymers. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1114‐1123, 2013  相似文献   

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