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     

Thermal processability and properties of highly filled poly(vinyl alcohol)/talc composite

Abstract

A highly filled PVA/talc composite was prepared through our invented thermal processing technology without using any coupling agent or compatibiliser. The results showed that compared with neat PVA, the melt temperature of the composite decreased and the degradation temperature increased, providing a big temperature window for thermal processing of PVA/talc composite. The composite melt exhibited shear thinning behaviour while its viscosity increased with increasing talc, still satisfied the requirement of thermal processing. The morphology analysis confirmed that talc was well dispersed in PVA, improving heat deflection temperature (HDT), tensile strength and modulus of PVA. When talc was 50 wt-%, the HDT, tensile strength and modulus of the composite were 115°C, 48 MPa, 1·23 GPa respectively, increased by 92, 16 and 150%, compared with PVA, and the elongation at break was 100% of the composite, confirming that the high filled PVA/talc composite was a novel PVA based material with excellent thermal and mechanical properties.     

Electromagnetic properties of aluminosilicate‐filled polymer composites of poly(vinyl alcohol)–poly(vinyl pyrrolidone)

Nanocomposites of aluminocilicate are of growing interest not only because they offer exceptional reinforcement at very low filler concentrations, but also because of their electromagnetic properties and natural origin. Aluminosilicate‐filled biodegradable composites of poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP) were prepared by a conventional solvent casting technique using glass plates as the casting surfaces. The aluminosilicate used in this study is a multicomponent natural clay material. Its average particle size is 23–24 nm. The dielectric and magnetic properties of composite materials of PVA‐PVP and aluminosilicate were investigated in wide frequency ranges from 1 MHz to 1 GHz. The complex permittivity spectra (ε* = ε′ – jε″) had a relaxation type frequency dispersion with an ill‐defined broad resonance line width of the dielectric losses (ε″). The magnetic properties of composites are very low and are independent of the filler concentration. The new nanobiocomposites are brick red in color and weakly ferromagnetic in nature. POLYM. COMPOS., 26:739–744, 2005. © 2005 Society of Plastics Engineers     

Mechanical,flow, and morphological properties of talc‐ and kaolin‐filled polypropylene hybrid composites

Polypropylene (PP) hybrid composites have been produced by compounding two types of mineral fillers, viz., talc and kaolin with PP copolymer using a twin screw extruder. The PP hybrid composite was injection‐molded into dumbbell specimen for tensile, flexural, and impact properties characterizations. MFI and SEM studies were used to characterize the flow and morphological properties of the PP hybrid composites. The result shows that most of the hybrid composites showed a significant decrease in flow, tensile, flexural, and impact properties compared with the single filler‐filled PP composites. However, a hybridization effect was seen for the PPT20K10 hybrid composites, through the synergistic coalescence of positive characteristics from 20 wt % of talc and 10 wt % of kaolin. This hybrid formulation have given an economically advantageous material with the mechanical properties (tensile, flexural, and impact) comparable to those of the talc‐filled PP composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 434–441, 2007     

Effect of filler treatments on rheological behavior of calcium carbonate and talc‐filled polypropylene hybrid composites

Commercial stearic acid treated calcium carbonate (CaCO₃) was used to make a comparative study on rheological behavior of the CaCO₃ and talc‐filled polypropylene (PP) hybrid composites with nontreated filler. Apparent shear viscosity and extrudate swell were investigated with variation of filler ratio and temperature with 30% by weight total of filler was used in PP composite. The Shimadzu capillary rheometer was used to evaluate shear viscosity and shear rate of the composite. It was found that the shear viscosities decrease with increasing shear rate. The apparent shear viscosity of the composite containing the stearic acid treated is slightly lower than untreated filler. Shear thickening behavior at higher shear rate has also shown by 15/15 treated composites at higher temperature about 220°C and investigation by SEM has proved that filler being densely packed at that condition. Treated composites also exhibit lower swelling ratio value than untreated composite, and swelling ratio also decreases linearly with increasing temperature and the die length–diameter ratio. It is believed that dispersion of filler play an important role not only on shear viscosity but also on swelling ratio of PP composite. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5421–5426, 2006     

Preparation and properties of some filled poly(vinyl chloride) compositions

Different samples of filled poly(vinyl chloride) (PVC) compositions were formulated from PVC, a polar plasticizer mixture consisting of dioctylphthalate (DOP) and a chlorinated paraffin, and variable proportions of a white filler such as barite, calcium carbonate, kaoline, quartz, or talc; a conductive filler such as High Abrasion Furnace (HAF) carbon black; or a hydrated mineral filler such as aluminium hydroxide, magnesium hydroxide, or calcium hydroxide. Epoxidized soybean oil as a heat stabilizer and sandorin red (BRN) pigment were added. Electrical and mechanical studies show that the incorporation of white fillers produces a plasticized PVC of good electrical insulation character whereas the addition of HAF carbon black produces a sample with some electrical conductivity; both of them have good mechanical properties. Of the hydrated fillers studied aluminium hydroxide has been found to impart the best fire retardancy and good electrical properties for electric wires and cables. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2657–2670, 1999     

Surface resistance and diffusion characteristics of toluene into calcium carbonate‐ and polymer‐coated calcium carbonate‐filled natural rubber composites

Solvent absorption has been followed in compression‐molded rubber vulcanizates for toluene in natural rubber (gum), calcium carbonate (CC)‐filled natural rubber composites, and polymer‐encapsulated calcium carbonate (PCC)‐filled natural rubber composites. The surface resistance is found to affect the absorption process of the composites. Diffusion from the sample sides is considered for thickness and the diffusion coefficients corrected accordingly. Aspects of the effect of PMMA on the equilibrium toluene take up, Fickian mode of transport; transport coefficients; activation parameters; and crosslink density are studied. The sorption results have been interpreted in terms of first‐order kinetic model. The crosslink densities calculated from equilibrium sorption successfully to explain the transport coefficient values of the composites. POLYM. ENG. SCI., 53:2487–2497, 2013. © 2013 Society of Plastics Engineers     

Comparison of the mechanical,thermomechanical, thermal,and morphological properties of pumice and calcium carbonate‐filled poly(phenylene sulfide) composites

In this study, it was aimed to investigate the mechanical, thermal, thermomechanical, and morphological properties of pumice and calcium carbonate (CaCO₃)‐filled poly(phenylene sulfide) (PPS) composites and compare the effect of these filler materials on the properties of composites. Mechanical test results indicate that %1 pumice and CaCO₃ addition increased the tensile strength value of PPS. With the %1 loading level of pumice, tensile strain of composites remained unchanged, but for other loading levels of both fillers, tensile strain of composites decreased. Hardness of composites increased with the addition of pumice to PPS matrix for all loading levels of pumice. The lowest damping factor peak intensity was observed for %1 pumice included composites. Morphological analyses results revealed that pumice particles are clearly embedded in the PPS matrix and covered with matrix. On the other hand, there are a number of microvioids that can be observed in the tensile fracture surfaces of CaCO₃‐filled composites. POLYM. COMPOS., 37:3160–3166, 2016. © 2015 Society of Plastics Engineers     

Experimental investigations of polypropylene and poly(vinyl chloride) composites filled with plerospheres

Plerospheres, defined here as superfine spherical particles (0.5–5 μm) separated from fly ash (rather than as other solid spherical particles, as some have used the term), are separated from coal fly ash but are dramatically different from it. Plerospheres can be used as polymer fillers to improve the properties of composites. With plerospheres used as fillers for polypropylene (PP) and unplasticized poly(vinyl chloride) (UPVC), the effects of the filler content, the particle sizes of the plerospheres, and the coupling agent on the composite properties were studied. The particle sizes of the plerospheres were 2 and 5 μm. The results suggested that the notched impact properties both at a normal temperature and a low temperature and the tensile and flexural properties of plerosphere/PP increased significantly when the content was increased from 0 to 30 wt % and further increased with the addition of a coupling agent. Differential scanning calorimetry indicated that the thermal properties of the plerosphere/PP composite improved. The surface characteristics and morphology of the impact fracture surface were examined in detail with scanning electron microscopy. The rheological performance of plerosphere/UPVC pipe composites obviously improved; the plasticizing time was shortened, and the maximum torque was reduced. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 126–131, 2004     

Thermal properties of poly(vinyl alcohol)/poly(diallyldi‐methylammonium chloride) interpenetrating polymer networks

Interpenetrating polymer networks (IPNs) constructed with poly(vinyl alcohol) (PVA) and poly(diallyldimethyl ammonium chloride) (PDADMAC) using a sequential IPN method were prepared. The thermal characterization of the IPNs was investigated by differential scanning calorimetry (DSC), dielectric analysis (DEA), and thermogravimtric analysis (TGA). Decreases in the melting temperature of PVA segments in IPNs were observed with increasing PDADMAC content using DSC. DEA was employed to ascertain glass transition temperature of IPNs. The thermal decomposition of IPNs was investigated using TGA, and thermal decomposition of IPNs could be decelerated by changing PVA content. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1346–1349, 2003     

Thermal properties of graphite‐loaded nitrile rubber/poly(vinyl chloride) blends

The thermal properties (thermal conductivity, thermal diffusivity, and specific heat capacity) of nitrile rubber (NBR)/poly(vinyl chloride) (PVC) blends were measured in the temperature range of 300–425 K. The incorporation of graphite into the NBR/PVC (30/70) matrix improved its thermal properties. Moreover, these properties slightly changed with the temperature. The thermal conductivity values of the prepared samples were compared with values modeled according to the Maxwell–Eucken, Cheng–Vachon, Lewis–Nielsen, geometric mean, and Agari–Uno models. The Agari–Uno model best predicted the effective thermal conductivity for the whole range of blend ratios and for the whole range of graphite contents in NBR/PVC (30/70)/graphite composites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Experimental and theoretic studies on sound transmission loss of laminated mica‐filled poly(vinyl chloride) composites

The effects of dioctyl phthalate and inorganic filler, mica, on the sound insulation property of poly(vinyl chloride) (PVC) were investigated in this work. The stiffness and mass laws, which are the common theoretic tools to predict the soundproof properties of materials, were used to analyze the sound transmission loss (STL). The experimental results revealed that the stiffness and mass laws can describe well the sound insulation property of PVC/mica composites. The stiffness and surface density are important factors influencing the improvement of STL. With the increase of content of mica, STL and resonance frequency, f_mn, of PVC/mica composites increase. Moreover, the change of STL in the stiffness‐ controlled region is more obvious than that in the mass‐controlled region, because the addition of mica in PVC leads to a greater increase in the stiffness. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Properties of nanoparticles filled soft poly(vinyl chloride) composites including antistatic plasticizer

Nanoparticles (NP) filled permanently antistatic poly(vinyl chloride) (PVC) composites, constituted of dibutyl phthalate (DBP) and antistatic plasticizer (AP) which included bis[2‐(2‐methoxyethoxy)ethyl]phthalate doped with sodium perchlorate (NaClO₄), were prepared in a Haaka torque rheometer. Surface resistivity measurement, mechanical test, scanning electron microscopy (SEM) investigation, and thermal gravimetric analysis (TGA)‐differential scanning calorimetry (DSC) analysis were used to investigate the comprehensive properties of PVC/AP/NP (100/40/x) (A40/NP) and PVC/AP/DBP/NP (100/40/40/x) (A80/NP) composites. The results demonstrated that the surface resistivity of A40/NP composites was lower than that of pure A40 composites at a humidity of 60% and 0.1% as the nano SiO₂ or TiO₂ content is 2 phr, respectively. Moreover, the surface resistivity of A40 composites was decreased by about half an order of magnitude even at the humidity of 0.1% when 2 phr of NP was added. The surface resistivity of A80/NP composites achieved the optimum value as the SiO₂ and TiO₂ content were 1 phr and 2 phr, respectively. Because the DBP functioned as small molecule plasticizer which endowed PVC composites with comparatively large free volume, the surface resistivity of A80/NP composites is much lower than that of A40/NP composites. The tensile strength and elongation at break of A40/NP (100/2) and A80/NP (100/2) were increased to some extent with respect to pure PVC/AP composites. DSC‐TGA analysis and rheological properties demonstrated that NP filled PVC composites processed good thermostability and thermoprocessability. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Tensile test of poly(vinyl chloride) filled with ground calcium carbonate particles

The fracture behavior of poly(vinyl chloride) filled with ground calcium carbonate particles during a tensile test was studied. The particles were prepared by crushing natural raw crystalline limestone. For this purpose, 10–50 parts of the particles having two different mean sizes (2 and 8 μm) without further surface treatment were mixed with 100 parts of poly(vinyl chloride) and 3 parts of lead stearate as a stabilizer using a mixing roll. A tensile test was carried out using a dumbbell specimen. As a result, the yield stress decreased with increase in the particle content; however, there was no significant influence of particle size. From scanning electron microscopic observations of the specimen's surfaces during the tensile test, it was found that the particle/matrix interfaces were delaminated and formed voids around the particles when the applied stress approached the yield stress, that is, the particles acted as voids and the matrix around the voids was plastically deformed effectively. These observations appear to be the reason for the decrease of yield stress by the incorporation of the particles. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 311–316, 1998     

Dopamine‐functionalized poly(vinyl alcohol) elastomer with melt processability and self‐healing properties

A dopamine‐functionalized poly(vinyl alcohol) (PVA) elastomer with melt processability and self‐healing properties was prepared by a new chemical route of graft modification, that is, PVA carboxylation and a carbodiimide reaction. The conventional modifier for PVA sacrificed the intrinsic hydrogen‐bonding interactions and dramatically decreased the mechanical strength. The modifier dopamine, as a catechol derivative, has two hydroxyl groups, which formed hydrogen bonds with the hydroxyl groups of PVA; it also has one benzene ring, which increased the thermal stability. We found that the introduction of dopamine into the PVA molecular structure lowered the melting point, improved the thermal stability, broke the crystalline structure, and enabled thermal processing. Moreover, the modified PVA possessed good mechanical properties, could be self‐healed, and is believed to have potential applications in many fields. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45072.     

Viscoelastic properties and extrusion processability of poly(vinyl butyral)

Rheological properties and flow instability at capillary extrusion of a random terpolymer composed of vinyl butyral, vinyl alcohol, and vinyl acetate, that is denoted as PVB in this article, are studied. It is found that the rubbery plateau modulus is 1.3 MPa at 100°C from the oscillatory shear modulus. Furthermore, the average molecular weight between entanglement couplings M_e is found to be 2670. Because of the relatively high value of , it shows rubbery region in the wide temperature range (90°C–180°C). At the capillary extrusion, the surface instability (shark‐skin failure) appears prior to volumetric melt fracture. The onset stress of the shark‐skin failure, ca. 0.18 MPa, is similar to that of polyethylene, although PVB used in this study has narrow molecular weight distribution. Moreover, the apparent slippage is not detected, presumably due to good adhesion to the die wall. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40337.     

Thermal and flammability studies of poly(vinyl alcohol) composites filled with sodium hydroxide

Poly(vinyl alcohol) (PVA) is a polymer of great value due to its wide spread applications. The present article describes the effect of sodium hydroxide on the flammability, thermal degradation, and tensile strength properties of PVA. The PVA/sodium hydroxide composite films at different loading levels of sodium hydroxide, i.e., 0.5, 1, 2, 3, and 4.5 wt % were prepared by solution casting technique. Dynamic thermogravimetry was used to study the thermal degradation behavior of samples at four different linear heating rates, i.e., 2.5, 5, 10, and 20 °C min^?1 under nitrogen atmosphere. The degradation activation energy values were calculated using reliable and preferred multiple‐heating rate methods. Limiting oxygen index (LOI) and UL 94 tests were carried out to check the flammability behavior of the samples. The presence of sodium hydroxide in PVA brought significant changes in the thermal and flammability performance. PVA/sodium hydroxide samples though showed lower initial decomposition temperature, but overall more thermal stability results as evidenced from the higher activation energy and char residue values. LOI and UL 94 tests indicate that sodium hydroxide greatly enhanced the flame retardancy of PVA/sodium hydroxide films. Based on the thermal and flammability level, the optimum concentration of sodium hydroxide is worked out. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Tribological properties of micro‐ and nanoparticles‐filled poly(etherimide) composites

It has been found that nano‐ or microsized inorganic particles in general enhance the tribological properties of polymer materials. In the present study, 5 vol % nano‐TiO₂ or micro‐CaSiO₃ was introduced into a polyetherimide (PEI) matrix composite, which was filled additionally with short carbon fibers (SCF) and graphite flakes. The influence of these inorganic particles on the sliding behavior was investigated with a pin‐on‐disc testing rig at room temperature and 150°C. Experimental results showed that both particles could reduce the wear rate and the frictional coefficient (μ) of the PEI composites under the applied testing conditions. At room temperature, the microparticles‐filled composites exhibited a lower wear rate and μ, while the nano‐TiO₂‐filled composites possessed the lowest wear rate and μ at elevated temperature. Enhancement in tribological properties with the addition of the nano‐particles was attributed to the formation of transfer layers on both sliding surfaces together with the reinforcing effect. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1678–1686, 2006     

Mechanical properties of poly(vinyl chloride)/wood flour/glass fiber hybrid composites

Short glass fibers were added to poly(vinyl chloride) (PVC)/wood flour composites as reinforcement agents. Unnotched and notched impact strength of PVC/wood flour/glass fiber hybrid composites could be increased significantly without losing flexural properties by adding type L glass fibers and over 40% of PVC. There was no such improvement when using type S glass fiber. The impact strength of hybrid composites increased along with the increment of the type L glass fiber content at a 50% PVC content. At high PVC contents, impact fracture surfaces were characterized by wood particle, glass fiber breakage and pullout, whereas interfacial debonding was the dominant fracture mode at higher filler concentrations. The significant improvement in impact strength of hybrid composites was attributed to the formation of the three‐dimensional network glass fiber architecture between type L glass fibers and wood flour.     

Mechanical and thermal properties of calcium carbonate‐filled PP/LLDPE composite

Polymer blends typically are the most economical means to develop new resins for specific applications with the best cost/performance balance. In this paper, the mechanical properties, melting, glass transition, and crystallization behavoir of 80 phr polypropylene (PP) with varying weights of linear low density polyethylene (LLDPE) at 10, 20/ 20 wt % CaCO₃, 30, 40, and 50 phr were studied. A variety of physical properties such as tensile strength, impact strength, and flexural strength of these blends were evaluated. The compatibility of these composite was examined by differential scanning calorimetry (DSC) to estimate T_m and T_c, and by dynamic mechanical analysis (DMA) to estimate T_g. The fractographic analysis of these blends was examined by scanning electron microscopy (SEM). It has been confirmed that increasing the LLDPE content trends to decreases the tensile strength and flexural strength. However, increasing the LLDPE content led to increases in the impact strength of PP/LLDPE blends. It was also found that up to 40 phr the corresponding melting point (T_m) was not effected with increasing LLDPE content. Each compound has more than one T_g, which was informed that there is a brittle‐ductile transition in fracture nature of these blends, the amount of material plastically deformed on the failure surface seems to increase with the increasing the LLDPE content. And PP/LLDPE blends at temperature (23°C) showed a ductile fracture mode characterized by the co‐existence of a shear yielding process; whereas at lower temperature (−20°C) the fractured surfaces of specimens appear completely brittle. The specimens broke into two pieces with no evidence of stress whitening, permanent macroscopic deformation or yielding. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011