Morphology,mechanical property,and processing thermal stability of PVC/La‐OMMTs nanocomposites prepared via in situ intercalative polymerization

Poly(vinyl chloride) (PVC) nanocomposites were prepared via an in situ intercalative suspension polymerization of vinyl chloride with four organic carboxylic acid salts (montmorillonite [MMT] units) containing thermally stable lanthanum ions. The effects of different lanthanum organic montmorillonites (La‐OMMTs) on the particle features and molecular weight were investigated. The transmission electron microscopy data indicated the formation of partially exfoliated or intercalated PVC/La‐OMMTs nanocomposites. The effect of different functional groups on the mechanical properties and processing thermal stability of PVC/La‐OMMT nanocomposites were investigated. Tensile testing and two‐roll mill processing results showed that La‐OMMTs could enhance the dynamic thermal stability and mechanical properties versus PVC pure resin and PVC/I.30P nanocomposites (composed of PVC and I.30P). This suggested that the double bond and amidogen group in La‐OMMTs could promote the dispersion of La‐OMMTs in the PVC matrix and also improve the adhesion between the La‐OMMTs and PVC matrix. The results have potential value in the industrial development of PVC/La‐OMMTs nanocomposites. J. VINYL ADDIT. TECHNOL., 26:97–108, 2020. © 2019 Society of Plastics Engineers     

The modification of lanthanum‐exchanged montmorillonite with anionic surfactants to enhance the thermal stability of polyvinyl chloride

A series of thermally stable lanthanum organic montmorillonites (La‐OMMTs) were successfully prepared by modifying Na‐MMT with anionic surfactants and lanthanum chloride. Fourier transform infrared spectroscopy and X‐ray diffraction indicated that the anionic surfactants resided in the interlayer spaces and expanded the MMT basal spacing from 1.23 nm to 3.3 nm. Thermogravimetric and differential thermal analysis (TG/DTA) results showed that the intercalation of sodium dodecyl sulfonate into the lanthanum organic MMT resulted in its excellent thermal stability. The use of the La‐OMMT samples in polyvinyl chloride (PVC) resins was tested, and the TG/DTG results revealed that the three La‐OMMTs could significantly enhance the thermal stability of PVC. The modified La‐OMMT with the highest thermal stability is expected to be useful in polymer/layered silicate nanocomposites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41535.     

Chemical effects of cationic surfactant and anionic surfactant used in organically modified montmorillonites on degradation and fire retardancy of polyamide 12 nanocomposites

Three kinds of organically modified Na⁺-montmorillonites (OMMTs), including two kinds of octadecylammonium modified montmorillonite with different contents of octadecylammonium and a kind of sodium dodecylsulfonate (SDSo) modified montmorillonite, were used to prepare polyamide 12 (PA12)/OMMT nanocomposites. Effects of the modifiers on degradation and fire retardancy of PA12/OMMT nanocomposites were investigated. Acid sites formed in cationic surfactant modified MMT via Hoffman decomposition could accelerate degradation of PA12 at high temperature. However, catalytic effect of the acid sites on carbonization of the degradation products promoted char barrier formation, which reduced heat release rate (HRR). Higher content of cationic surfactant in OMMT is beneficial to fire retardancy of PA12 nanocomposites and the dispersion states of OMMT have assistant effects. In contrast, Na⁺-montmorillonite (Na-MMT) and anionic surfactant modified MMT (a-MMT) could not form acid sites on the MMT layers; in this case, fire retardancy of PA12/Na-MMT appears to have no improvement and PA12/a-MMT appears to have limited improvement.     

Flame‐retardant and smoke‐suppressant properties of zinc borate and aluminum trihydrate‐filled rigid PVC

The effects of zinc borate (ZB), aluminum trihydrate (ATH), and their mixture on the flame‐retardant and smoke‐suppressant properties of poly(vinyl chloride) (PVC) as well as their mechanism for flame retardancy and smoke suppression were studied through the limiting oxygen index (LOI) test, smoke density test, TGA, GC–MS, and SEM. The results show that incorporation of a small amount of ZB, ATH, and their mixture can greatly increase the LOI of PVC and reduce the smoke density of PVC during combustion. The mixture of ZB with ATH has a good synergistic effect on the flame retardance and smoke suppression of PVC. TGA and GC–MS analyses results show that incorporation of a small amount of ZB, ATH, and their mixture greatly promotes the char formation of PVC and decreases the amount of hazardous gases such as benzene and toluene released in PVC during combustion. Their mechanism is also proposed. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 3119–3127, 2000     

纳米阻燃抑烟PVC的研究进展

PVC是一种应用广泛的高分子材料,但因其具有热稳定性差、易燃烧、发烟量大的缺点而限制了发展,因此PVC的阻燃与抑烟成为阻燃科学研究领域的关键问题之一。纳米型阻燃抑烟剂克服了传统型阻燃抑烟剂添加量大、阻燃抑烟效果不明显的缺点,为研究和解决PVC阻燃抑烟提供了一个新途径。本文介绍了PVC纳米阻燃抑烟剂的制备方法、表征手段及其在PVC中的应用以及PVC降解、阻燃与抑烟的表征,最后简要论述PVC阻燃抑烟的发展趋势。     

Enhancement of organoclay on thermal and flame retardant properties of polystyrene/magnesium hydroxide composite

Organoclay (organically modified montmorillonite, OMMT) was introduced to the composite of polystyrene/magnesium hydroxide (PS/MH) by melt compounding. The structure of the obtained PS/MH/OMMT composite was characterized by X‐ray diffraction and transmission electron microscopy. Thermal degradation behavior and flame retardancy of the composite were investigated by various means. It is shown that the PS/MH/OMMT composite has an intercalated nanostructure with the PS chains intercalated between the OMMT layers and the MH particles dispersed evenly in the PS matrix. Compared with the PS/MH composite containing identical amount of flame retardant, the introduction of OMMT has increased the thermal degradation temperature and lowered the mass loss rate at high temperatures. The PS/MH/OMMT nanocomposite can produce a more continuous and compact charred residue layer upon degradation both in air and burnt in flame than the PS/MH composite. Because of formation of this highly thermally stable and insulating charred residue layer, the nanocomposite exhibits much improved thermal endurance, flame retardancy, smoke suppression, and dripping resistance. Moreover, the combination of MH and OMMT makes the composite more difficult to ignite and decreases the release of toxic gas. The advantage of the PS/MH/OMMT nanocomposite is more pronounced in the early stage of combustion. POLYM. COMPOS., 37:746–755, 2016. © 2014 Society of Plastics Engineers     

Effect of OMMTs on flame retardancy and thermal stability of poly(ethylene‐co‐vinyl acetate)/LDPE/magnesium hydroxide composites

The aim of this study was to prepare poly (ethylene‐co‐vinyl acetate) (EVA)/ low density polyethylene (LDPE)/magnesium hydroxide (MH) composites applicable in cable industry with required flame retardancy. For this reason, two types of organo‐modified montmorillonites (OMMT) with different surface polarites (Cloisite 15A and Cloisite 30B) at various concentrations, and also combination of these two OMMTs with overall loadings of 2 wt % and 5 wt % were used. The samples were compounded using a twin screw extruder with total (MH + OMMT) feeding of 55 wt % and 60 wt %. Limiting oxygen index (LOI) of the samples containing 2 wt % of OMMTs increased about 16% and dripping was suppressed according to vertical burning test (UL‐94V). Thermogravimetric results of EVA/LDPE/MH samples containing OMMT showed that the beginning of second step degradation was shifted about 50°C to higher temperatures. The composite tensile strength results showed enhancement by incorporating some amount of nanoclays with EVA/LDPE/MH composites. Scanning electron microscopy images confirmed that MH particles had better wetting by EVA matrix in presence of nanoclays. Oxidative induction time of the EVA/LDPE/MH/OMMT nanocomposites was 140 min, which was more than that of the samples without OMMT (20 min). Employing the equal weight ratios of the two OMMTs demonstrated a synergistic effect on flame retardancy of the samples according to the both tests results (LOI, UL‐94V). X‐ray diffraction analysis of the samples confirmed the intercalation/semiexfoliation structure of nanosilicate layers in the bulk of EVA/LDPE matrix. This led to longer elongation at break and thermal stability of Cloisite 15A based nanocomposites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40452.     

Preparation,characterization, and properties of poly(vinyl chloride)/organophilic‐montmorillonite nanocomposites

Poly(vinyl chloride) (PVC)/organophilic‐montmorillonite (OMMT) nanocomposites were prepared by direct melt intercalation. PVC/compatibilizer ((vinyl acetate) copolymer (VAc))/OMMT nanocomposites were also prepared by melt intercalation by a masterbatch process. The effect of OMMT content on the nanostructures and properties of nanocomposites was studied. The nanostructures were studied by wide angle X‐ray diffraction (WAXD) and transmission electron microscopy (TEM). The linear viscoelastic properties and dynamic mechanical properties of PVC/OMMT nanocomposites were also investigated by an advanced rheometric expansion system (ARES) rheometer. The results showed that partially exfoliated and partially intercalated structures coexisted in the PVC/OMMT and PVC/VAc/OMMT nanocomposites. The mechanical properties test results indicated that the notched Charpy impact strengths of nanocomposites were improved compared to that of pristine PVC and had a maximum value at 1 phr OMMT loadings. The compatibilizer could further improve the impact strengths. But the existence of OMMT decreased the thermal stability of PVC/OMMT and PVC/VAc/OMMT nanocomposites. The linear viscoelastic properties test results indicated the dependence of G′ and G″ on ω shows nonterminal behaviors, and they had better processibility compared with pristine PVC. However, the glass transition temperatures of PVC/OMMT nanocomposites almost had little change compared to that of pristine PVC. POLYM. COMPOS., 27:55–64, 2006. © 2005 Society of Plastics Engineers     

Synergistic effects of zinc oxide in montmorillonite flame‐retardant polystyrene nanocomposites

In this study, two‐dimensional organic montmorillonite (OMMT) and one‐dimensional needlelike ZnO were used as flame retardants of polystyrene (PS). Polystyrene/organic montmorillonite (PMT) and polystyrene/organic montmorillonite/zinc oxide nanocomposites (PMZs) with different weight ratios were prepared by melt intercalation. Information on the morphologies and structures of the PS nanocomposites was obtained with Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results indicate that a mixed exfoliated–intercalated structure was observed in the PMT and PMZs. Dynamic mechanical thermal analysis showed that both the storage modulus and glass‐transition temperature values of the PMT and PMZs were significantly improved compared with those of the neat PS. The mechanical property tests showed that the bending modulus values of both PM5 (PS/OMMT weight ratio = 95:5) and PMZs increased compared with that of pristine PS. PMZ1 (PS/OMMT/ZnO weight ratio = 94:5:1) provided no decrease in the tensile strength in comparison with PS. A synergistic effect was observed between OMMT and ZnO; this resulted in improvements in the flame retardancy and dynamic mechanical properties in the PMZs. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43047.     

新型无卤阻燃聚丙烯的制备与性能研究

采用碱式硫酸镁晶须(MOS)与有机蒙脱土(OMMT)作为阻燃剂制备了阻燃聚丙烯(PP),研究了MOS和OMMT用量对阻燃PP力学性能和阻燃性能的影响,并通过热失重分析(TGA)和锥形量热仪(CONE)对材料进行了表征。结果表明:MOS对PP有良好的增强阻燃作用,少量OMMT的加入可以进一步提高阻燃PP的阻燃性能。当MOS与OMMT用量分别为40.0%和3.0%时,阻燃PP的OI为28.5%,其热释放速率峰值(pHRR)和平均热释放速率(mHRR)分别为156.5kW/m2和112.9kW/m2,比基体树脂分别下降了83.3%和72.1%,同时其抑烟性能也大为改善。     

Synergistic effect of organo‐montmorillonite on intumescent flame retardant ethylene‐octene copolymer

Nanocomposite of thermoplastic elastomer ethylene‐octene copolymer/maleated ethylene‐octene (POE/POE‐g‐MAH) with organo‐montmorillonite (OMMT, 11 wt %) as masterbatch have been obtained by melt blending and it has been characterized by transmission electron microscopy (TEM). Flame retardant POE/POE‐g‐MAH/OMMT/ammonium polyphosphate‐pentaerythritol (APP‐PER) (an intumescent flame retardant with 75 wt % ammonium polyphosphate and 25 wt % pentaerythritol) composites were prepared by using melting processing to study their structures, flame‐retardancy, thermal, and mechanical properties. TEM showed exfoliated structures throughout POE/POE‐g‐MAH/OMMT masterbatch and POE/POE‐g‐MAH/OMMT/APP‐PER nanocomposites. Synergistic effect was observed between OMMT and APP‐PER resulting in significant improvements on thermal stability, flame‐retardancy and mechanical properties in the POE/POE‐g‐MAH/OMMT/APP‐PER nanocomposites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synergistic flame retardant effects of activated carbon and molybdenum oxide in poly(vinyl chloride)

The synergistic effects of activated carbon (AC) and molybdenum oxide (MoO₃) in improving the flame retardancy of poly(vinyl chloride) (PVC) were investigated. The effects of AC, MoO₃ and their mixture with a mass ratio of 1:1 on the flame retardancy and smoke suppression properties of PVC were studied using the limiting oxygen index and cone calorimeter tests. It was found that the flame retardancy of the relatively cheaper AC was slightly weaker than that of MoO₃. In addition, the incorporation of AC and MoO₃ greatly reduced the total heat release and improved smoke suppressant property of PVC composites. When the total content of AC and MoO₃ was 10 phr, PVC/AC/MoO₃ had the lowest peak heat release rate and peak smoke production rate values of 173.80 kW m^?2 and 0.1472 m² s^?1, which represented reductions of 47.3 and 59.9%, respectively, compared with those of PVC. Furthermore, thermogravimetric analysis and gel content tests were used to analyze the flame retardant mechanism of AC and MoO₃, with results showing that AC could promote early crosslinking in PVC. Char residue left after heating at 500 °C was analyzed using scanning electron microscopy and Raman spectroscopy, and the results showed that MoO₃ produced the most compact char, with the smallest and most organized carbonaceous microstructures. © 2017 Society of Chemical Industry     

氨基硅油对氢氧化镁及有机蒙脱土阻燃LLDPE的影响

用氢氧化镁(MH)和有机蒙脱土(OMMT)作为阻燃剂制备了阻燃线型低密度聚乙烯(LLDPE),研究了氨基硅油(ASO)对阻燃LLDPE力学性能及阻燃性能的影响。通过锥形量热仪(CONE)和热失重分析(TGA)对材料进行了表征。结果表明:ASO提高了阻燃性能和抑烟效果。当ASO用量为2%时,阻燃LLDPE的热释放速率峰值(pHRR)和平均热释放速率(mHRR)分别降低到169.6kW/m2和86.7kW/m2,比加入ASO前下降了20.5%和9.7%;烟产生速率峰值(pSPR)和总生烟量(TSP)分别降低到0.017m2/s和0.4m2。此外,ASO提高了材料的断裂伸长率和冲击强度。     

Development of nanocomposites based on organically modified montmorillonite and plasticized PVC with improved barrier properties

Montmorillonite (MMT) was organically modified with tributyl citrate (TBC). Organoclays (OMMTs) were processed with diisononyl phthalate (DINP)‐plasticized polyvinyl chloride (PVC) to form polymer nanocomposites. The produced composite materials showed a contradictory change in properties to that expected of a layered silicate nanocomposite, with a decreased E‐modulus and increased gas permeability compared with a material without OMMT. It was experimentally shown that the TBC modifier was extracted from the OMMT and was dispersed in the PVC/DINP matrix, whereupon the OMMT collapsed and formed micrometer‐sized agglomerates. Further investigation revealed that TBC has a significant effect on the gas permeability and the E‐modulus, even at low additions to a DINP‐plasticized PVC. A PVC nanocomposite with the TBC acting as both the OM for MMT and as the primary plasticizer was produced. This material showed a significantly increased E‐modulus as well as a decrease in gas permeability, confirming that it is possible to develop a nanocomposite based on plasticized PVC, if both the organo‐modification of the MMT and the formulation of the matrix are carefully selected. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42876.     

Thermal stability and flame retardance properties of acrylonitrile-butadiene-styrene/polyvinyl chloride/organophilic Fe-montmorillonite nanocomposites

In the article, acrylonitrile-butadiene-styrene/polyvinyl chloride/organophilic Fe-montmorillonite (ABS/PVC/Fe-OMT) nanocomposites were prepared by melt intercalation method. In order to determine if the presence of iron ion in the structure of organophilic montmorillonite (OMT) lattice can affect thermal, flame retardance and smoke suppressant properties in the ABS/PVC blends. ABS/PVC/organophilic natural montmorillonite (Na-OMT) nanocomposites were prepared as the comparable sample. Fe-MMT and Na-MMT were treated by cetyl trimethylammonium bromide (CTAB). The information on morphologies and structures of ABS/PVC/OMT nanocomposites was obtained using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The thermal properties of the nanocomposites were characterized by thermogravimetric analysis, and flame retardant properties were obtained via limiting oxygen index (LOI), UL-94 vertical burning test and smoke density. The nanocomposites, based on Fe-OMT, exhibited better flame retardance, better smoke suppressant properties, and lower degradation degree than those of pure ABS/PVC blends and the ABS/PVC/Na-OMT nanocomposites.     

Effect of intercalation agent on the structure and properties of OMMT and RTV/OMMT composites

Novel room‐temperature vulcanized silicone rubber (RTV)/organic montmorillonite (OMMT) composites have been prepared. Di(2‐oxyethyl)‐12 alkane‐3 methyl‐amine chloride and hydrogen silicone oil were used as intercalation agents to treat Na⁺‐montmorillonite and form two kinds of OMMTs. The structure and properties of OMMT were characterized by Fourier transform infrared spectroscopy and X‐ray diffraction (XRD). The intercalation mechanism of different types of intercalation agents was proposed. RTV/OMMT composites were prepared using these OMMTs. Properties such as viscosity, hardness, tensile strength, elongation at break, and thermal stability were researched and compared. A combination of swelling test, XRD and transmission electronic microscopy studies was used to characterize the structure and reinforcing mechanism of these OMMTs. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Low‐melting sulfate glasses as additives to semirigid PVC and their flame retardant and smoke suppressant properties

The role of low‐melting sulfate glasses (LMSG) as additives on the flame retardant and smoke suppressant properties of semirigid poly(vinyl chloride) (PVC), as well as the mechanism for flame retardancy and smoke suppression, were studied through the Limiting Oxygen Index (LOI) test. Smoke Density Rating (SDR) test, DTA‐TG, and SEM. The results show that the LMSG have good smoke suppressant properties. When the PVC compound contains 40 parts of LMSG, the SDR value will be reduced by about 45%. The Cu²⁺, Zn²⁺, Mn²⁺, and Ni²⁺ sulfates, as well as MoO₃, cause PVC to crosslink and form char, and the melt can protect not only the char formed during combustion and thermal degradation, but also undecomposed polymer. That is the main mechanism for flame retardation and smoke suppression when the additives melt. The mechanical properties of the PVC compounds containing different levels of LMSG were also studied.     

Preparation and properties of a novel elastomeric polyurethane/organic montmorillonite nanocomposite

A novel elastomeric polyurethane (EPU)/organic montmorillonite (OMMT) nanocomposite has been synthesized. 18 Alkane‐3 methyl‐amine chloride and dihydroxethyl‐12 alkane‐3 methyl‐amine chloride were used as intercalation agents to treat Na⁺‐montmorillonite and for forming two kinds of OMMTs. The better OMMT was chosen according to fourier transform infrared spectroscopy (FTIR) and wide angle X‐ray diffraction (WAXD). Three types of EPU/OMMT nanocomposites were synthesized by in situ polymerization of EPU, with different amounts of OMMT. A combination of FTIR, WAXD, and transmission electronic microscopy (TEM) studies showed that EPU/OMMT composites were on the nanometer scale and the segmented structure of EPU was hindered by the presence of the OMMT, due to the reaction between toluene diisocyanate (TDI) and the intercalation agents. Properties such as tensile property, differential scanning calorimeter (DSC), and thermogravimetric analysis (TGA) were researched and compared. Results showed that the EPU/3% OMMT had the best physical and mechanical properties because of its uniform dispersion of the organic silicate layers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3578–3585, 2006     

Flame retardancy,antifungal efficacies,and physical–mechanical properties for wood/polymer composites containing zinc borate

This work aimed to examine flame retardancy, antifungal performance and physical–mechanical properties for silane‐treated wood–polymer composites (WPCs) containing zinc borate (ZnB). ZnB with content from 0.0 to 7.0 wt% was added to WPCs, and silane‐treated wood contents were varied. The polymers used were poly(vinyl chloride) (PVC) and high‐density polyethylene (HDPE). The decay test was performed according to the European standard EN 113. Loweporus sp., a white‐rot fungus, was used for antifungal performance evaluation. Antifungal performance was observed to decrease with wood content. Incorporation of ZnB at 1.0 wt% significantly increased the antifungal performance of WPCs. ZnB content of greater than 1.0 wt% lowered the antifungal properties of WPCs. The results suggested that the wood/PVC composite exhibited better antifungal performance than the wood/HDPE composite. The addition of wood flour to PVC and HDPE decreased flame retardancy, whereas the incorporation of ZnB retained the flame retardancy. ZnB was found to be more appropriate for wood/PVC than wood/HDPE as a result of hydrogen chloride generated from the dehydrochlorination reaction of PVC. The results indicated that the addition of ZnB did not affect the physical‐mechanical properties of neat polymers and the composites. Copyright © 2016 John Wiley & Sons, Ltd.     

Morphology,mechanical properties,and thermal stability of rigid PVC/clay nanocomposites

PVC/Poly(ε‐caprolactone) (PCL)/organophilic‐montmorillonite (OMMT) and PVC/Polylactide (PLA)/OMMT nanocomposites were prepared by a two‐step process. PCL/OMMT and PLA/OMMT master batches were prepared by melt blending using a two‐roller mill first, and then they were blended with PVC via extrusion. PVC/OMMT nanocomposites were also prepared using a two‐roller mill. Morphology, mechanical properties, and thermal stability were investigated. The formation of exfoliated or intercalated nanocomposites was confirmed by X‐ray diffraction (XRD) and transmission electron microscopy (TEM). Only the PVC/PCL/OMMT nanocomposite showed both higher tensile strength and stiffness than unfilled PVC. Atomic force microscopy (AFM) indicated dependency of this behavior not only on the clay dispersion, but also on the adhesion between the OMMT and the polymer matrix. Furthermore, scanning electron microscopy (SEM) showed that the large plastic deformation of the PVC/PCL matrix also contributed to the strength increase of the PVC nanocomposites. The effect of PCL/OMMT on the improvement of the thermal stability of PVC was remarkable while the effect of PLA/OMMT was moderate. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers.