Effect Of Organo-modified Montmorillonite Research Articles

Effects of OMMT on the aging behaviors of halogen-antimony flame-retarded LGFPA6 composites: Flammability and thermal degradation kinetics

After a long-term thermo-oxidative exposure, compared to the long-glass-fiber reinforced polyamide 6 composite containing halogen-antimony flame retardants (FR/LGFPA6), substitution of a certain content of flame retardants with organo-modified montmorillonite (OMMT) was found to positively affect the FR/LGFPA6 composite in some cases (i.e. flammability and thermal degradation kinetics). The aged OMMT/FR/LGFPA6 composite not only was less flammable but also behaved better in the formation of char residues. All the calculated apparent activation energy obtained by the methods of Friedman, Flynn-Wall-Ozawa and Coats-Redfern in a dynamic measurement showed an obvious increase for the OMMT/FR/LGFPA6 composite after aging, a theoretical evidence for its improved flame retardancy.

Effects of organo-modified montmorillonite on the tribology performance of bismaleimide-based nanocomposites

Abstract Poly(allyl condensed polynuclear aromatic-bismaleimide) (ACOPNA–BMI) with different loadings of an organo-modified montmorillonite (OMMT) nanocomposites were successfully prepared via in situ suspension polymerization. Exfoliation/intercalation phenomena were detected using transmission electron microscopy (TEM) and X-ray diffraction (XRD). Positive effects of the exfoliated platelets on the wearable and thermal behaviours were achieved by varying the OMMT load. The lowest friction coefficient of ACOPNA–BMI/2.0 wt.% OMMT was 0.46 at a wear rate of 0.508 × 10− 6 mm3/Nm, which was superior to that of pure ACOPNA–BMI copolymer resin. The thermostabilities of the materials were assessed by thermogravimetric analysis (TGA). The temperature at the maximum rate of thermal decomposition of ACOPNA–BMI/3 wt.% OMMT was 480 °C, which was much higher than that of the pure ACOPNA–BMI copolymer (436 °C). The nanocomposite obtained, which is a suitable wearable material, can be widely used for protecting drilling tools in petroleum engineering applications due to its thermostability and good self-lubrication properties.

Effects of ENR and OMMT on barrier and tensile properties of LDPE nanocomposite film

The effects of organo-modified montmorillonite (OMMT) nanoclay and epoxidized natural rubber (ENR) content on the gas barrier, tensile, and the thermal properties of nanocomposite films based on low-density polyethylene (LDPE) are investigated. Linear low-density polyethylene-grafted maleic anhydride (LLDPE-g-MA) is used as a compatibilizer to obtain better dispersion of the nanoclay in the blends. The blends, with various amounts of ENR (0–10) wt%, are melt-compounded and extruded using a blown film extrusion single screw. The tensile properties of films are studied in machine direction (MD). The gas permeability of films is studied via constant pressure and a soap bubble flow meter. The melting and crystallization behaviors of films are examined via differential scanning calorimetry (DSC). Chemical interactions of composite blends are examined via Fourier transform infrared (FTIR) spectroscopy. An addition of 6 wt% nanoclay improved the tensile modulus by about 11 %. It further reduced the oxygen permeability by about 83 %. Although introducing OMMT decreased the percentage of crystallinity (XC), the presence of LLDPE-g-MA in the nanocomposite enhanced the property due to better intercalation between the phases. Incorporation of ENR caused an increase in the Young’s modulus for compatibilized nanocomposite systems, attributed to an interaction among clay, compatibilizer, and ENR, and cross-linking effects of ENR molecules. However, ENR decreased the permeability of the film due to the ability of amorphous regions to form crystallized structures during the blown process, and cross-linking effects of ENR. In addition, ENR reduced the XC of nanocomposites due to an interference that exists in the form of ENR molecular incorporation. The FTIR spectra showed that the maleic anhydride group in LLDPE-g-MA reacted in situ with the epoxy groups of ENR, which was an evidence of grafting reaction.

Effect of Organo-Modified Montmorillonite on Thermal Properties of Bacterial Poly(3-hydroxybutyrate)

Nanocomposites based on biodegradable poly(3-hydroxybutyrate) (PHB) and two types of organically modified layered silicates, cloisite 30B (C30B) and montmorillonite grafted-poly(ϵ-caprolactone) (MPCL), were prepared through solution intercalation technique. The thermal properties of PHB/nanocomposites at different organoclay contents (5 and 10%) were investigated using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The DSC results showed that the dispersed MPCL enhanced the rate of crystallization of PHB from glassy and molten states, whereas C30B retarded the crystallization of PHB from glassy state and enhanced its crystallization from molten state. Kinetics of thermal degradation was studied using Ozawa and Kissinger methods.

Study of the Effect of Organomodified Montmorillonite on PP/APP/Si-E System

In this article, organomodified montmorillonite (OMMT) was applied as synergistic agent in Polypropylene(PP)/Ammonium polyphosphate (APP)/Elastomer containing silicon(Si-E)system. The effect of OMMT on this system was investigated by thermo gravimetric. analysis (TGA), Fourier transform infrared spectrometer (FT-IR), scanning electron microscopy (SEM) and limited oxygen index (LOI). The results show that the flame-retardancy properties of PP/APP/Si-E composites enhanced in the presence of OMMT. LOI was enhanced slightly and the char residue was increased. The impact strength of the PP composite was significantly improved after adding OMMT. The weight loss difference shows that there was a synergetic interaction between OMMT and PP/APP/Si-E composite.

The effect of organo-modified montmorillonite on mechanical and barrier properties of linear low-density polyethylene/low-density polyethylene blend films

In this study, the effect of organo-modified montmorillonite on mechanical and gas barrier properties of nanocomposite films of linear low-density polyethylene/low-density polyethylene blends was investigated. Two different compatibilizers, polyethylene grafted maleic anhydride and polypropylene grafted maleic anhydride, were used to obtain a better dispersion of the nanoclay in the blends. The blend samples containing various amounts of the clay were melt compounded and then blown to films. Mechanical properties of the films were studied in machine and transverse directions. A constant volume-variable pressure method was used to determine the gas permeability of the films. Addition of the 4 parts per hundred nanoclay improved the tensile modulus in machine direction by about 59% and that in transverse direction by about 100%. It further reduced the oxygen permeability by about 38%.

Investigation of various factors effects on mechanical properties of Poly(propylene)/organo-modified Montmorillonite/Magnesium hydroxide composites

The combined effects of organo-modified montmorillonite (O-MMT) gallery polarity, surface modification of magnesium hydroxide (MDH), maleic anhydride grafted polypropylene (MA-g-PP) and antioxidant (Irganox 1010) addition, together with mixing time and rotor speed of the mixer on the measured flexural modulus, maximum (max) flexural (flex) strength and impact strength of the composites were studied. A two-level factorial experimental design of these variables was used to examine their simultaneous effects. The 16 composite samples were prepared by melt mixing in an internal mixer at 200 °C and their properties were measured. The flexural modulus and max flex strength of the samples containing high level of both MDH and O-MMT reached the highest and lowest amount respectively. Effect of the factors and their interactions on impact strength and max flex strength was almost in the same order and by decreasing the amount of O-MMT/or MDH, these properties were increased. The regression equations showed the most effective factors and their interactions which were in good agreement with the obtained results. Addition of 1%w/w O-MMT to 50%w/w MDH/PP composites led to the best mechanical properties.

Effect of organo-modified montmorillonite on flame retardant poly(1,4-butylene terephthalate) composites

In this paper, the effect of organo-modified montmorillonite (OMMT) on a novel intumescent flame retardant (IFR) system was studied in poly(1,4-butylene terephthalate) (PBT) composites containing microencapsulated ammonium polyphosphate (MAPP) and melamine cyanurate (MC). Nanocomposite morphology was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Thermal decomposition analysis was studied via thermogravimetric analysis (TGA). Combustion behavior was investigated by microcombustion calorimeter (MCC), limited oxygen index (LOI), and UL-94 test. Residues obtained after samples treated in muffle furnace at 500°C under air condition for 10 min were analyzed through X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). It was found that the addition of OMMT improved the flame retardancy of PBT/IFR composites significantly. A mass of microcomposite structure particles formed in the heating or combustion process of PBT/IFR/OMMT nanocomposites were found for the first time in the SEM images, which is strong evidence to confirm the migration or accumulation of montmorillonite and carbonaceous-silicate materials during the heating or combustion process. Copyright © 2010 John Wiley & Sons, Ltd.

An effect of OMMT on the anti‐reversion in NR/CR blend system

AbstractThe influence of dispersed organomodified montmorillonite (OMMT) on curing behaviors of natural rubber (NR)/chloroprene rubber (CR) blend was investigated. The preparing procedure includes premixed rubber individually with its additives and then the two components were blended according to gum weight ratio for NR to CR is 75/25. Sulfur was chosen as the vulcanizing agent, and the research on vulcanization was carried through the rotor‐Rheometer at 143°C. Transmission electron microscopy showed the dispersion of OMMT in the rubber blends and detected little OMMT migrated into the NR phase. The scorch time (t10), optimum vulcanizing time (t90), and reversion phenomenon were both measured by the curing curve; meanwhile, the crosslinking densities and mechanical properties were determined through equilibrium swelling‐method, magnetic resonance crosslink density spectrometer, and tensile tests. By comparing the test results, an interesting phenomenon was discovered and furthermore was verified that the addition of OMMT can obviously modify the reversion resistance of the binary blend. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Effects of organo-modified montmorillonite on strengths and permeability of cement mortars

Organo-modified montmorillonites (OMMT) which have been widely used in polymer/clay nano-composites are employed here as fillers and reinforcements in cement mortars. The ratio of quartz sand and cement is 2.75 while the water/cement ratios of 0.40, 0.485 and 0.55 are considered for the cement mortars we studied. Experimental results indicate that the coefficients of permeability of cement mortars could be 100 times lower if a lower dosage of OMMT micro-particles is added. At the same time, the compressive and flexural strengths of cement mortars can be even increased up to 40% and 10%, respectively. It is also found that the optimal dosage of OMMT micro-particles to give higher compressive and flexural strengths and a lower coefficient of permeability for cement mortars is less than 1%. Meanwhile, the microstructure of cement mortars is characterized by using SEM, EDS and MIP to evaluate the effects of OMMT micro-particles on the improvements of strengths and permeability of cement mortars.