Structure and properties of polypropylene/clay nanocomposites compatibilized by solid‐phase grafted polypropylene

Polypropylene/organic‐montmorillonite (PP/OMMT) nanocomposites were prepared via a solid‐phase PP graft (TMPP) with a higher grafting level as the compatibilizer. The effects of the compatibilizer on the structure and properties of PP/OMMT nanocomposites were investigated. The structure of the nanocomposites were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results showed that when the weight ratio of TMPP and OMMT is greater than 1:1, the OMMT can be dispersed in PP matrix uniformly at the nanoscale. The mechanical properties of the nanocomposites reached a maximum when the weight ratio of TMPP and OMMT is 1:1, although more uniform dispersion was achieved at a higher content of TMPP. The mechanical properties of the nanocomposites decrease with the content of TMPP. The crystallization behavior, dynamic rheological property, and thermal stability of the nanocomposites were investigated by differential scanning calorimetry (DSC), dynamic rheological analysis, and thermal gravimetric analysis (TGA), respectively. Due to the synergistic effects of TMPP and OMMT on the crystallization of PP, the crystallization peak temperature of the nanocomposites increased remarkably compared with that of the neat PP. TMPP shows β‐phase nucleating ability and OMMT promotes the development of β‐phase crystallite. The nanocomposites show restricted melt flow and enhanced temperature sensitivity compared with the neat PP. The thermal stability of the nanocomposites is obviously improved compared with that of the neat PP. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers.     

丁腈橡胶/聚氯乙烯/有机蒙脱土纳米复合材料的结构与性能

采用胶乳共沉法和直接共混法制备了丁腈橡胶／聚氯乙稀／有机蒙脱土（NBR／PVC／OMMT）纳米复合材料。通过X射线衍射（XRD）法和透射电子显微镜（TEM）法对NBR／PVC／OMMT纳米复合材料的结构进行了袁征,并研究了复合材料的力学性能、耐油性能和耐老化性能。结果表明,2种方法所获得的复合材料是插层型纳米复合材料;胶乳共沉法制备的纳米复合材料中OMMT的分散更为均匀,其力学性能、耐油性能和耐老化性能优于直接共混法制备的复合材料。     

Tuning the interlaminar shear strength and thermo-mechanical properties of glass fiber composites by incorporation of (3-mercaptopropyl) trimethoxysilane-functionalized carbon black

The incorporation of functionalized nanoscale fillers into traditional glass fiber/unsaturated polyester (GF/UPE) composites provides a more robust mechanical attributes. The current study demonstrates the potential of 3-mercaptopropyl trimethoxysilane (MPTS)-functionalized carbon black (f-CB) for enhancing the thermo-mechanical properties of GF composites. The composites infused with 1, 3 and 5 wt% of pristine and MPTS-functionalized CB were fabricated by hand lay-up and hot press processing. Tensile testing, interlaminar shear strength (ILSS) testing and dynamic mechanical analysis were used to evaluate the performance of nanocomposites. Fourier transform infrared spectroscopy validated the MPTS functionalization of CB. Pristine CB-loaded nanocomposites exhibited marginal improvement in ultimate tensile strength (UTS), ILSS and thermo-mechanical properties. However, with the addition of f-CB, the improvement in all the studied properties was more substantial. The inclusion of 5 wt% f-CB increased the elastic modulus and UTS by 16 and 22%, respectively, whereas the ILSS was enhanced by 36%, in comparison to the neat GF composite. The scanning electron microscope analysis of fractured ILSS samples revealed better fiber-matrix adhesion and compatibility in f-CB-loaded nanocomposites. At the same filler weight percentage, the storage modulus at 25 °C was ~ 19% higher than that of neat composite. The f-CB inclusion resulted in increment of T _g by ~ 13 °C over the T _g of neat GF/UPE composite (~ 109 °C). These improvements were due to the chemical connection of f-CB to the UPE matrix and GF surface. With such improvements in thermal and mechanical properties, these nanocomposites can replace the conventional GF composites with prominent improvements in performance.     

Mechanical and rheological properties of PP/SEBS/OMMT ternary composites

The microstructure and mechanical properties of polypropylene (PP)/OMMT binary nanocomposites and PP/styrene‐6‐(ethylene‐co‐butylenes)‐6‐styrene triblock copolymer (SEBS)/OMMT ternary nanocomposites were investigated using X‐ray diffraction (XRD), transmission electron microscopy (TEM), and rheology and electromechanical testing machine. The results show that the organoclay layers are mainly intercalated and partially exfoliated in the PP‐based nanocomposites. The additions of SEBS and OMMT have no significant effect on the crystallization behavior of PP. At the same time, it can be concluded that the polymer chains of PP and SEBS have intercalated into the organoclay layers and increase the gallery distance after blending process based on the analytical results from TEM, XRD, and rheology, which result in the form of a percolated nanostructure in the PP‐based nanocomposites. The results of mechanical properties show that SEBS filler greatly improve the notched impact strength of PP, but with the sacrifice of strength and stiffness. OMMT can improve the strength and stiffness of PP and slightly enhance the notched impact strength of PP/PP‐g‐MA. In comparison with neat PP, PP/OMMT, and PP/SEBS binary composites, notched impact toughness of the PP/SEBS/OMMT ternary composites significantly increase. Moreover, the stiffness and strength of PP/SEBS/OMMT ternary nanocomposites are slightly enhanced when compared with neat PP. It is believed that the synergistic effect of both SEBS elastomer and OMMT nanoparticles account for the balanced mechanical performance of the ternary nanocomposites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

The physical and mechanical properties of beta‐nucleated polypropylene/montmorillonite nanocomposites

Polypropylene (PP) and polypropylene/polypropylene‐g‐maleic anhydride/ organomontmorillonite (PP/PP‐g‐MA/OMMT) nanocomposites were modified with 0.05 to 0.3% (w/w) of the aryl amide β‐nucleator to promote the formation of hexagonal crystal modification (β‐phase) during melt crystallization. The nonisothermal crystallization behavior of PP, PP/PP‐g‐MA/OMMT and β‐nucleated PP/PP‐g‐MA/OMMT nanocomposites were studied by means of differential scanning calorimetry. Structure‐property relationships of the PP nanocomposites prepared by melt compounding were mainly focused on the effect and quantity of the aryl amide nucleator. The morphological observations, obtained from scanning electron microscopy, transmission electron microscopy and X‐ray diffraction analyses are presented in conjunction with the thermal, rheological, and mechanical properties of these nanocomposites. Chemical interactions in the nanocomposites were observed by FT‐IR. It was found that the β‐crystal modification affected the thermal and mechanical properties of PP and PP/PP‐g‐MA/OMMT nanocomposites, while the PP/PP‐g‐MA/OMMT nanocomposites of the study gained both a higher impact strength (50%) and flexural modulus (30%) compared to that of the neat PP. β‐nucleation of the PP/PP‐g‐MA/OMMT nanocomposites provided a slight reduction in density and some 207% improvement in the very low tensile elongation at break at 92% beta nucleation. The crystallization peak temperature (T_cp) of the PP/PP‐g‐MA/OMMT nanocomposite was slightly higher (116°C) than the neat PP (113°C), whereas the β‐nucleation increased the crystallization temperature of the PP/PP‐g‐MA/OMMT/aryl amide to 128°C, which is of great advantage in a commercial‐scale mold processing of the nanocomposites with the resulting lower cycle times. The beta nucleation of PP nanocomposites can thus be optimized to obtain a better balance between thermal and mechanical properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

Effects of thermoplastic polyurethane on the properties of poly(lactic acid)/organo‐montmorillonite nanocomposites based on novel vane extruder

Polylactic acid (PLA)/organo‐montmorillonite (OMMT) nanocomposites toughened with thermoplastic polyurethane (TPU) were prepared by melt‐compounding on a novel vane extruder (VE), which generates global dynamic elongational flow. In this work, the mechanical properties of the PLA/TPU/OMMT nanocomposites were evaluated by tensile, flexural, and tensile tests. The wide‐angle X‐ray diffraction and transmission electron microscopy results show that PLA/TPU/OMMT nanocomposites had clear intercalation and/or exfoliation structures. Moreover, the particles morphology of nanocomposites with the addition of TPU was investigated using high‐resolution scanning electronic microscopy. The results indicate that the spherical TPU particles dispersed in the PLA matrix, and the uniformity decreased with increasing TPU content (≤30%). Interestingly, there existed abundant filaments among amount of TPU droplets in composites with 30 and 40 wt% TPU. Furthermore, the thermal properties of the nanocomposites were examined with differential scanning calorimeter and dynamic mechanical analysis. The elongation at break and impact strength of the PLA/OMMT nanocomposites were increased significantly after addition of TPU. Specially, Elongation at break increased by 30 times, and notched impact strength improved 15 times when TPU loading was 40 wt%, compared with the neat PLA. Overall, the modified PLA nanocomposites can have greater application as a biodegradable material with enhanced mechanical properties. POLYM. ENG. SCI., 54:2292–2300, 2014. © 2013 Society of Plastics Engineers     

Biodegradable PPC/(PVA-TPU) ternary blend blown films with enhanced mechanical properties

Biodegradable films of poly(propylene carbonate)/poly(vinyl alcohol)-thermoplastic polyurethane [PPC/(PVA-TPU)] ternary blends were successfully prepared by melting blending method. The mechanical properties of poly(propylene carbonate) blown film were greatly improved by blending PPC with PVA-TPU. In order to afford the melt processing of PVA, the PVA-TPU binary blend was firstly prepared using thermoplastic polyurethane as a polymeric plasticizer. The rheological behavior, mechanical properties and morphology of these blends were studied. Considering its melt viscosity and thermally processing temperature, the PVA-50%TPU, as a modifier, was blended with PPC to prepare PPC/(PVA-TPU) ternary blend. SEM observation revealed a basic one-phase morphological structure with very good interfacial adhesion between the extremely blurred PPC and PVA-TPU two components. Meanwhile, the miscibility of the ternary components was verified by only one glass-transition temperature obtained from DMA tests. The tensile strength and tear strength of PPC/(PVA-TPU) blown films were determined at different temperatures. The results demonstrate that the mechanical properties of PPC/(PVA-TPU) films were enhanced dramatically at low temperature when compared with neat PPC. At room temperature, PPC/30 %(PVA-50%TPU) blown film exhibited a tensile strength of 26 MPa, and an elongation at break of 484.0 %. Its tear strength in the take-up direction is 124.1 kN/m, and the one in machine direction is 141.9 kN/m. At a low temperature of 0 °C, PPC/30 %(PVA-50%TPU) exhibited a tensile strength of 40.7 MPa and tear strength of 107 kN/m, which are 153 % and 142 % of those of neat PPC respectively. The blending of PPC with the PVA plasticized with TPU provides a practical way to extend the application of the new biodegradable polymer of PPC in the area of blown films.     

Morphology, rheology and dynamic mechanical properties of PP/EVA/clay nanocomposites

This paper reports on morphology, rheology and dynamic mechanical properties of polypropylene (PP)/ethylene vinyl acetate (EVA) copolymer/clay nanocomposite system prepared via a single step melt compounding process using a twin screw micro-compounder. Scanning electron microscopic (SEM) investigations revealed that the dispersed phase droplet size was reduced with incorporation of an organo-modified montmorillonite (OMMT). This reduction was more significant in presence of a maleated PP (PP-g-MAH) used as compatibilizer. Phase inversion in the compatibilized blends caused a further decrease in PP droplet size. The OMMT gallery spacing was higher in nanocomposites with EVA as matrix which could be attributed to higher tendency of OMMT nanoparticles towards EVA rather than PP. This enhanced tendency was confirmed by rheological analysis too. Transmission electron microscopy (TEM) results also showed that the majority of OMMT nanoparticles were localized on the interface and within EVA droplets. According to dynamic mechanical analysis, the compatibilized nanocomposites showed higher storage and loss moduli due to better dispersion of OMMT layers. The modulus enhancement of nanocomposites as a function of OMMT volume fraction was modeled by Halpin-Tsai’s-Nielsen expression of modulus for nanocomposites. The results of modeling suggested that the aspect ratio of the intercalated OMMT, in the form of Einstein coefficient (K _E), plays a determining role in the modulus enhancement of nanocomposites.     

Preparation and Performance of High-Barrier Low Density Polyethylene/Organic Montmorillonite Nanocomposite

Montmorillonite (MMT) was first modified with dodecyl dimethylbenzyl ammonium (DDA) salt and octadecyl trimethyl ammonium (OTA) salt. Then low density polyethylene (LDPE)/organic montmorillonite (OMMT) nanocomposites were prepared by twin-screw extruder and hot-press. Transmission electron microscopy (TEM) results showed that OMMT layers were homogeneously intercalated into the LDPE matrix. In terms of MMT, the modification effect of OTA is superior to that of DDA. CO₂ and O₂ barrier properties of nanocomposites were increased by 7 times and 4 times with 0.5 wt.% OTA-MMT loading, respectively. At 2 wt% OTA-MMT loading, water vapor permeability of LDPE has also decreased about 2.5 times. Compared with pure PE film, 49.5% and 178% improvement of tensile strength of nanocomposites films were obtained by addition of only 4 wt.% DDA-MMT and OTA-MMT, respectively. In addition, with only 0.5 wt.% OMMT loading, the onset degradation temperature of nanocomposites increases by 23°C and 26°C for LDPE/DDA-MMT and LDPE/OTA-MMT, respectively.     

Effect of organoclay on the gas barrier properties of natural rubber nanocomposites

Natural rubber nanocomposites have been prepared with organically modified montmorillonite clay. The nanocomposites have been characterized by X‐ray diffractometry and transmission electron microscopy. The gas‐barrier properties of the nanocomposites have been studied for three different gases viz., oxygen, nitrogen, and CO₂ gases. The natural rubber–organoclay composites exhibit outstanding gas‐barrier properties compared to the neat rubber. Various models have been applied to predict the decrease in permeability in nanocomposites. All other models except Bharadwaj model give low values of calculated aspect ratio. Dynamic mechanical analysis has been carried out to investigate the role of the constrained region on the permeability of the nanocomposites. The permeability decrease of the organoclay nanocomposites is found to have good qualitative correlation with the volume of the constrained region. POLYM. COMPOS.,, 2012. © 2012 Society of Plastics Engineers     

A Study on Structure and Mechanical Properties of Polyurethane/Organic-Montmorillonite Nanocomposites

The intercalated nanocomposites of polyurethane (PU) with organic-montmorillonite (OMMT) treated by cetryltrimethyl ammonium bromide was prepared. The interlayer spacing of PU/OMMT nanocomposites was 3–4 nm. The interface interaction of PU/OMMT nanocomposites was improved compared to that of PU/montmorillonite (MMT) composites. The orderly arrangement of the PU chains was hindered because of strong interface interaction between the silicate layers dispersed in the nanometer and PU chains. By adding 2 wt% OMMT to PU, tensile strength and tear strength of the PU/OMMT composites were increased from 10.5 MPa and 36.4 KN/m to 13.8 MPa and 42.2 KN/m, respectively. The tensile strength and tear strength increased with OMMT content firstly, reaching its maximum when the OMMT content was 8 wt%. After that, the tensile strength and tear strength decreased with the further increase of the OMMT content. Compared to that of PU, the elongation at break of the PU/OMMT nanocomposites increased, indicating that the stretch of PU/OMMT nanocomposites increased.     

水滑石/丁腈橡胶纳米复合材料的制备及性能研究

采用乳液复合法制备水滑石(LDHs)/丁腈橡胶(NBR)纳米复合材料,并对其结构和性能进行研究。结果表明:复合材料中LDHs均匀分散在NBR基体中;与NBR胶料相比,LDHs/NBR复合材料的物理性能和气体阻隔性能明显提高;当LDHs/NBR用量比为1/20且LDHs用量为1份时,LDHs/NBR复合母胶/溴化丁基橡胶并用胶的气体阻隔性能较好。     

Radiation induced modification of NBR and SBR montmorillonite nanocomposites

Nanocomposites of two different kinds of rubber (acrylonitrile-butadiene rubber NBR and styrene butadiene rubber SBR)/organo-montmorillonite nanocomposites modified by hexadecyltrimethyl ammonium bromide were prepared by the reactive mixing intercalation method in the presence of trimethylolpropane trimethylmethacrylate (TMPTMA). The influence of gamma irradiation on the morphology and properties of the rubber nanocomposites was investigated. Intercalated polar or unsaturated matrices (e.g., NBR and SBR)/OMMT nanocomposites can be obtained, which was confirmed by X-ray diffraction (XRD). The clay layers could be uniformly dispersed in the rubber matrix on the nanometer level. Mechanical tests showed that the nanocomposites had good mechanical properties as compared to the neat composites. The results also showed that the irradiated NBR/OMMT nanocomposites had higher thermal stabilities than irradiated SBR/OMMT nanocomposites.     

Mechanical,thermal, and rheological behavior of ethylene methyl acrylate‐MWNT nanocomposites

Mechanical, thermal, and rheological properties of ethylene methyl acrylate (EMA) composites reinforced with multiwalled carbon nanotubes (MWNTs) have been reported here. Morphological analyses revealed that MWNTs are more uniformly dispersed in EMA upto 3.5 wt% MWNTs loading. Uniform dispersion of MWNTs in EMA matrix leads to decreased crystallinity and increased crystallite size. These are reflected in the mechanical and thermal properties of the composites. The storage moduli of the composites significantly increase by the incorporation of MWNTs, particularly at higher temperatures. The nanocomposites register a slightly higher viscosity than that of neat EMA depending on the contents of MWNTs. Storage modulus (in dynamic shear) increases especially at higher frequency levels due to increased polymer–filler interactions. Dynamic and steady shear rheological properties register a good correlation in regard to the viscous versus elastic response of the nanocomposites. The morphology correlates well with the dynamic rheological characteristics of these nanocomposites. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

Epoxy-Modified Mesua ferrea L. Seed-Oil-Based Polyester/Clay Nanocomposites

The nanocomposites of epoxy-modified Mesua ferrea L. seed-oil-based polyester resin were designed with 0-5 wt% loadings of organophillic montmorrilonite (OMMT). X-ray diffraction, transmission electron microscopy, and scanning electron microscopy studies revealed very good dispersion of OMMT with exfoliated structure in the matrix. The effects of OMMT on the curing, thermal, mechanical, and rheological behaviors of the nanocomposites were also investigated. Two times’ improvement in tensile strength, 2 kg increment in scratch hardness, and 68°C enhancement in thermal degradation temperature were obtained for the nanocomposites with 5 wt% OMMT loading compared to pristine polyester.     

Preparation and rheological characterization of intercalated polystyrene/organophilic montmorillonite nanocomposite

Polystyrene (PS)/organophilic montmorillonite (OMMT) clay nanocomposites were prepared by a solvent casting method using chloroform as a cosolvent. Intercalation of the OMMT in the PS matrix was achieved as revealed by X‐ray diffraction. The IR spectra of the products indicated that the OMMT is homogeneously dispersed in the PS matrix. A thermogravimetric analysis (TGA) showed that the onset temperature increases linearly with the clay content. The glass‐transition temperature of the PS, examined using differential scanning calorimetry, had a trend similar to that from the TGA. The rheological properties of the PS/OMMT nanocomposites were also investigated via a rotational rheometer with a parallel plate geometry, and they exhibited sharper shear thinning and increased storage and loss modulus with clay content. Furthermore, the shear viscosity obtained from the steady shear experiment was well correlated with the complex viscosity obtained from the oscillatory experiment via the Cox and Merz relation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2106–2112, 2003     

溴化丁基橡胶/天然橡胶/有机蒙脱土纳米复合材料的结构与性能研究

采用机械混炼法制备了溴化丁基橡胶/天然橡胶/有机蒙脱土(BIIR/NR/OMMT)纳米复合材料,对其亚微观结构与性能进行了表征。实验结果表明:OMMT片层以剥离形式均匀分散于橡胶基体中;OMMT能够明显促进橡胶硫化反应,并使BIIR和NR两相的交联同步性加强;纳米复合材料具有优异的物理机械性能和热稳定性能。     

Effect of Organo-Modified Montmorillonite on the Morphology and Properties of SEBS/TPU Nanocomposites

In this study, novel polystyrene-b-poly(ethylene-butylene)-b-polystyrene (SEBS)/thermoplastic polyurethane (TPU)/organo-modified montmorillonites (OMMT) nanocomposites were prepared by melt mixing. Three different organo-modified montmorillonites, DK2, DK3, and DK4 (listed in descending order of hydrophilicity) were selected. The compatibilizing and reinforcing effects of OMMT on the structure, morphology, thermal stability, mechanical and rheological properties of the SEBS/TPU blends were studied. It was found that the hydrophilic DK2 nanoparticles were largely located in the continuous TPU phase and partially dispersed at the phase interphase, whereas DK3 and DK4 nanoparticles were preferentially located at the phase interface with an intercalated/exfoliated and intercalated structure, respectively. Scanning electron microscopy (SEM) results showed that SEBS/TPU/OMMT nanocomposites exhibited a more densely organized and interconnected structure compared with SEBS/TPU blends. Better thermal property was achieved after adding DK3, with the tensile properties of the SEBS/TPU increased considerably. Rheological analysis revealed that hydrophilic DK2 nanoparticles were more effective in improving rheology properties and showed a more pronounced nonlinear effect. The prepared SEBS/TPU/OMMT nanocomposites displayed desired thermal, mechanical and rheological properties, which are important for many applications. POLYM. ENG. SCI., 60:850–859, 2020. © 2020 Society of Plastics Engineers     

环氧树脂改性聚乳酸/低熔点尼龙6/蒙脱土纳米复合材料结构与性能

通过熔融共混法制备了环氧树脂改性聚乳酸 (ePLA)/低熔点尼龙6 (LMPA6)/蒙脱土纳米复合材料。XRD和DSC结果表明,结晶度随着有机蒙脱土（OMMT）加入量的增加呈先增加后减小的趋势。流变行为结果表明,ePLA/LMPA6/OMMT纳米复合材料的黏性响应占主导地位,另外,随着OMMT加入量的增加,储能模量和损耗模量也增加。阻隔性能测试结果表明,OMMT的加入能够有效地改善纳米复合材料的阻隔性能。热重结果表明,OMMT的加入能够显著提高纳米复合材料的热稳定性能。TEM测试结果表明,OMMT加入量较少时,OMMT容易在基体中形成均一的纳米结构。力学性能分析表明,随着OMMT质量分数的增加,纳米复合材料的拉伸强度、断裂伸长率和冲击强度均出现先上升后下降的趋势,且当OMMT质量分数为3%时,纳米复合材料的力学性能均达到最大值,与未加OMMT时相比,分别提高了9.7%、37.8%和35.9%。     

Preparation and properties of chlorosulfonated polyethylene/organomontmorillonite nanocomposites

Chlorosulfonated polyethylene (CSPE)/organomontmorillonite (OMMT) nanocomposites were prepared by a melt intercalation method. The microstructure of the nanocomposites was characterized by transmission electron microscopy and X‐ray diffraction. The effects of the OMMT content on the mechanical properties and swelling behavior of the nanocomposites were investigated. The improvement in the thermal stability of the nanocomposites was determined by thermogravimetric analysis. Transmission electron microscopy and X‐ray diffraction showed that CSPE was intercalated into OMMT. When the OMMT content was lower than 12 wt %, the nanocomposites showed excellent tensile properties, which was attributed to nanometer‐scale dispersion. The introduction of a small amount of OMMT also improved the thermal stability and swelling behavior, which was attributed to the gas barrier action of the OMMT layers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010