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The polypropylene (PP) composites filled with flame retardants (including aluminum hydroxide (Al(OH)3), magnesium hydroxide (Mg(OH)2), and zinc borate (ZB)) were prepared, and the composites were separately loaded with polyolefin elastomer (POE) and nanometer calcium carbonate (nano-CaCO3). The tensile properties and the fire residue morphology of the specimens after burning for these three groups of composites were measured. The results were shown that the tensile fracture strength and the Young’s modulus increased while the tensile yield strength and the tensile elongation at break ( δb) decreased with increasing flame-retardant volume fraction. At the same flame-retardant content, the δb values of the PP/Al(OH)3/Mg(OH)2/ZB/nano-CaCO3/POE composite were the highest in the three groups of composites. The fire residue in the pyrolysis zone of the specimens increased corresponding to the increased flame-retardant volume fraction and with loading the nano-CaCO3 and POE, especially at low-flame-retardant concentration. The reinforcing and the flame-retarded mechanisms of the composites were discussed.

The influence of the size and content of multi-walled carbon nanotubes (MWCNTs) on the end pressure effects of polypropylene (PP) composite melts during capillary extrusion flow was investigated, with the test temperature varying from 190°C to 230°C and apparent shear rate ranging from 50 s−1 to 3000 s−1. The results showed that the end pressure drop increased with increasing apparent shear rates, while decreased with increasing test temperature, and the sensitivity of the end pressure drop to apparent shear rate for the composites was higher than that for the unfilled PP. The end pressure drop increased with increasing weight fraction and the specific surface area of the MWCNTs. The end pressure drop increased almost linearly with increasing the aspect ratio of the MWCNTs. Moreover, the end pressure effect mechanisms of the composite melts during a capillary extrusion flow were discussed.

The influence of tension rates and filler size on the tensile properties of polypropylene (PP) composites separately reinforced with graphene nano-platelets (GNPs) were investigated at room temperature within a tension rate range from 20 to 300 mm/min using a universal materials tester. The results showed that the Young's modulus, the tensile yield strength and the tensile fracture strength of these three PP composite systems increased obviously when tension rate was lower than 100 mm/min, and then increased slightly with increasing tension rate. The tensile elongation at break of these three composite systems decreased obviously when tension rate was lower than 100 mm/min, and then decreased slightly with increasing tension rate. The morphology of the tensile specimens of the composite was observed after tensile tests. Finally, the reinforcement mechanisms of the composites under different tension rates were discussed.

The melt spinning flow behaviour of a high-density polyethylene (HDPE) blended with a low-density polyethylene (LDPE) was studied using a melt spinning technique in temperature ranging from 160 to ...

The high-density polyethylene (HDPE) conductive composites filled separately with carbon fibers (CFs), ethylene-vinyl acetate copolymer (EVA), and three kinds of carbon blacks (CBs) (including diff...

The melt strength and drawability of a low-density polyethylene (LDPE), a high-density polyethylene (HDPE) and HDPE/LDPE blends during extension flow were studied using a Rheotens test method under die extrusion temperature ranging from 160 to 200 °C and die extrusion rates varying from 9 to 36 mm/s. The results showed that the melt strength of the HDPE, the LDPE and the blends decreased with increasing die extrusion temperature while it increased with increasing die extrusion rate. The drawability of the HDPE, the LDPE and the blend melts could be improved through increasing die extrusion temperature and reducing die extrusion ratio. The dependence of the melt strength of the HDPE, the LDPE and the blend melts on the die extrusion temperature approximately obeyed the Arrhenius equation.

To avoid the defects caused by the hydrogen evolution and improve the corrosion and wear properties of the electroplated films in the traditional aqueous bath electrodeposition, a supercritical carbon dioxide (Sc-CO2) emulsion was proposed to electrodeposite ternary nanocrystalline Co−Ni−P alloy films. Microstructure, corrosive and tribological properties of the Co−Ni−P films were investigated and compared with the ones electroplated by conventional method. The results show that the Co−Ni−P films produced with Sc-CO2 assisted electrodeposition exhibit a more compact microstructure. The preferred orientation plane of hcp (110) for the Co−Ni−P films produced in conventional aqueous bath is changed to be hcp (100) for the one prepared in emulsified Sc-CO2 bath. The microhardness, corrosion resistance and tribological properties of the Co−Ni−P films are substantially improved with the assistance of Sc-CO2 in the electrodeposition bath.

Melt shear flow behavior and melt shear viscosity are important characterization of processing properties for polymeric materials. The effects of microencapsulated red phosphorus (MRP) content and experimental conditions on the melt shear flow behavior of the polypropylene (PP) composites were investigated using a torque rheometer. It was found that the melt shear viscosity, the torque, and energy consumption at balance state of the composites increased nonlinearly with increasing MRP weight fraction while decreased slightly with increasing temperature, the maximum torque increased with increasing the roller speed, and the dependence of the melt shear viscosity and the energy consumption at balance state on temperature roughly obeyed the Arrhenius equation. These findings would provide useful data for processing these flame-retardant PP composites.

The reversible nonlinear electrical conductive properties of high-density polyethylene composites filled separately with carbon black (CB), ethylene-vinyl acetate copolymer, and carbon fiber (CF) were measured using a four-electrode method. It was found that these composites presented significant reversible nonlinear electrical conductive behavior under these experimental conditions; the correlation between the current density and the electrical field intensity was linear in a bi-logarithmic coordinate system; both the crossover current density and the conductivity were approximately a linear function of the conductivity in a bi-logarithmic coordinate system; there was a synergic effect in the electrical conductivity percolation threshold between the CB and CF in the matrix, and the percolation threshold decreased with increasing the Brunauer–Emmett–Teller specific area of the CB.

The influence of extrusion conditions (temperature ranging from 170 to 220 °C, loads varying from 1.2 to 12.5 kg) and high-density polyethylene (HDPE) content on swelling behavior of polyoxymethylene (POM)/ethylene-vinyl acetate copolymer (EVA)/HDPE blend melts was examined. It was found the melt die-swell ratio of the blends decreased approximately linearly with rise in temperature, while it increased as a quadratic function with increasing shear rate or shear stress. The melt die-swell ratio increased with increasing HDPE weight fraction under constant test temperature, and the effect of temperature on the sensitivity of the melt die-swell ratio to the HDPE weight fraction was insignificant, while the effect of load on the melt die-swell ratio was significant. The correlation between the melt die-swell ratio of the blends and the HDPE weight fraction followed a quadratic relation. The melt extrudate swell behavior mechanisms of the blends during the die extrusion flow are discussed.

The high-density polyethylene (HDPE) composites filled with four kinds of carbon blacks (CB) were prepared to investigate the effects of the size and content of the CB on the electrical properties of the HDPE/CB composites. It was found that the composites presented conductive percolation behavior, the CB with different size filled-systems had different percolation thresholds; the higher the structure property of the CB, the larger the particle surface area, and the smaller the particle size, the better was the conductivity, and the lower was the percolation threshold of the composites. In addition, the HDPE/CB composites showed significant positive temperature coefficient (PTC) effect and negative temperature coefficient effect. The bigger the filler particle diameter, the higher was the PTC intensity of the HDPE composite systems under the same CB weight fraction.

The influence of heat treatment on the electrical conductive behavior of carbon black (CB) filled high density polyethylene (HDPE) composites was investigated. The results showed that the effects of annealing temperature on the resistivity and the PTC intensity of the HDPE/CB composites were significant; the resistivity and the PTC intensity of the composites varied with increasing number of thermal cycles; while the variation became small after the third thermal cycle. Furthermore, the variation of the resistivity was 1.7 times higher than that of the composites without annealing, and the variation of the PTC intensity of the composites was 0.22, which were smaller than those of the specimens without heat treatment. A suitable annealing heat treatment could reduce the resistivity and enhance the PTC intensity of the composites; it was also helpful to improve the stability of the properties of the composites and the repeatability of the PTC effect.

The impact fracture strength, melt volume flow rate (MVR) and melt density of polypropylene composites filled separately with two flame retardants (aluminum hydroxide and magnesium hydroxide), zinc borate (ZB), polyolefin elastomer (POE) and nanometer calcium carbonate (nano-CaCO 3 ) were measured to identify the effects of the flame-retardant content on the flow properties and impact fracture toughness. The results showed that the MVR decreased with increasing flame-retardant weight fraction ( ϕ f ) while it increased with increasing load; the melt density increased approximately linearly with increasing ϕ f while the influence of the ZB, nano-CaCO 3 , POE and load on the melt density was insignificant. The V-notched Izod impact strength increased when ϕ f was lower than 30 wt.%, then it decreased slightly with increasing ϕ f . The value of the V-notched Izod impact strength reached a maximum at ϕ f about 20 wt.%.

The reinforcing effects of highly effective flame retardant magnesium hydroxide (FMX) content on the tensile and flexural properties of filled polypropylene (PP) composites were investigated within the FMX weight fraction range from 5 to 60 wt%. It was found that the Young's modulus and flexural modulus increased approximately linearly while the tensile yield strength and tensile fracture strength decreased slightly with increasing the FMX weight fraction. When the FMX weight fraction was lower than 20%, the tensile elongation at break decreased considerably, and then decreased slightly; the flexural strength increased when the FMX weight fraction was lower than 30%, and then decreased slightly. The tensile properties increased with increasing rate of tension. Moreover, the tensile yield strength of the composites was estimated using an equation proposed in previous work, and good agreement was shown between the predicted and the measured data.

The influence of the content and length-diameter ratio ( l f / d f ) of carbon fiber (CF) on the electric conductive behavior of the reinforced high density polyethylene (HDPE) composites was investigated. It was found that both the HDPE composites filled with CF with large l f / d f (short-cut) and the HDPE composites filled with CF with small l f / d f (triturated) presented obvious conductive percolation behavior; the percolation threshold value of the HDPE/short-cut CF composites was about 7.5 vol%, but when the triturated CF volume fraction was 18%, the percolation threshold value of the HDPE/triturated CF composite was obvious higher than that of the HDPE/short-cut CF composites. The positive temperature coefficient (PTC) transition temperature of the composites moved from low temperature to high temperature direction. For the same PTC transition temperature, the triturated CF weight fraction needed was at least two times higher than that of the short-cut CF.

The thermal properties and thermal stability of polypropylene (PP) composites separately filled with graphene nanoplatelets (GNPs) with three different sizes were measured using a differential scanning calorimetry and a thermal gravimetric analyser. The results showed that the values of the melting temperature of the composites were higher than that of the unfilled PP; the thermal stability increased with increasing the weight fraction and lateral dimension of GNPs in the case of low filler concentration, while the effect of the GNPs thickness on the thermal stability was insignificant; the onset decomposition temperature increased with increasing the GNPs lateral dimension, while the maximum thermal decomposition rate increased first and then decreased with increasing the GNPs weight fraction. The thermal stability improvement should be attributed to the sheet barrier function of the GNPs.

The thermal conductivities of a medium density polyethylene composites filled separately with two different thermal conductive fillers including graphite, cuprum, and aluminum oxide (Al2O3), an epoxy composites filled respectively with two different thermal conductive fillers including silicon nitride, aluminum hydroxide, Al2O3 and aluminum nitride, and a polypropylene composites filled with aluminum hydroxide and magnesium hydroxide were estimated using a thermal conductivity equation of polymer multiphase composites. This equation was based on a new heat transfer model, and the parameters were easily determined. It was found that the estimated thermal conductivities of the three composites systems were approximately close to the experimental measured data reported in literature. In addition, the predictions were roughly close to the estimations from the Agari model. POLYM. ENG. SCI., 2016. © 2016 Society of Plastics Engineers

The influence of multi-walled carbon nanotubes (MWCNTs) size including average diameter and length-diameter ratio on the melt flow behavior of polypropylene composites were investigated by means of a capillary rheometer in a temperature ranging from 190 to 230 °C and under apparent shear rates varying from 100 to 4000 s−1. It was found that the melt shear flow approximately obeyed the power law; the values of the melt shear viscosity increased with an increase of the filler weight fraction, while decreased with increasing the average diameter of the MWCNTs; the dependence of the melt shear viscosity on temperature roughly obeyed the Arrhenius equation; the relationship between the melt shear viscosity and the MWCNTs weight fraction was almost linear; the sensitivity of the melt apparent shear viscosity to the MWCNTs weight fraction was weakened with increasing the MWCNTs average diameter.

The influence of the filler size and content on the crystallization behavior of polypropylene (PP) composites filled with three multi-walled carbon nanotubes (MWCNTs) with different sizes was investigated by means of a differential scanning calorimetry (DSC). It was found that the values of the onset crystallization temperature, crystallization peak temperature and end crystallization temperature increased with increasing MWCNT weight fraction and with decreasing filler average diameter; the value of the crystalline degree of the composites increased slightly with increasing filler weight fraction. The values of the crystalline degree of the composites filled with MWCNTs with wide length-diameter ratio and small specific surface area were the lowest when the MWCNT weight fraction was lower than 4%, which can be attributed to weak interaction between the matrix and inclusions due to small specific surface area. Moreover, the total crystallization rate of the composites filled with a small amount of the MWCNTs could be significantly increased.

The polyfluorinated ethylene propylene (FEP)/polypropylene (PP) blend was compounded at melt state in a twin-screw extruder. The melt dynamic viscoelasticity of FEP/PP blends was measured using a Bohlin rheometer with the extended temperature option under experimental conditions with temperature scope from 270°C to 280°C and shear frequency ( ω) varying from 10−2 to 101 s−1. The results showed that the shear storage modulus ( G′) and shear loss modulus ( G″) increased nonlinearly, while the dynamic complex viscosity ( η*) decreased slightly with increasing ω. The G′ and G″ were an exponential function of ω. The G′, G″, and η* of the blend melts decreased with an addition of the PP weight fraction [Formula: see text], and the relationship between them might be expressed by a multinomial third-order equation. This phenomenon might be attributed to the difference in viscoelasticity between the FEP melt and PP melt. The value of tan δ of the blend melts achieved the maximum at about 100 s−1.

The tensile properties of polypropylene (PP) composites filled separately with three kinds of graphene nano-platelets (GNPs) with different size were measured using a universal materials tester at room temperature and rate of extension of 50 mm/min. It was found that the values of the Young's modulus of the composites increased, the values of the tensile yield strength and tensile fracture of the composites increased slightly while the values of the tensile elongation at break decreased with increasing the GNPs weight fraction. The reinforcement of the composites could be attributed to the relatively big interfacial area and good interfacial adhesion between the matrix and the GNPs.

The tensile and combustion properties of polypropylene/polyolyaltha olefin composites filled with intumescent flame retardant (IFR) and nanometer calcium carbonate (nano-CaCO3) were measured. It was found that the values of the Young’s modulus of the composites increased almost linearly, while the values of the tensile yield strength and tensile fracture strength of the composites decreased with increasing the IFR weight fraction; the values of the elongation at break of the composites decreased quickly when the IFR weight fraction was lower than 10 wt%, and then varied slightly when the IFR weight fraction was higher than 10 wt%. Moreover, the morphology of the specimens after combustion was observed and the frame retardant mechanisms of the composites were discussed.

Polymers reinforced with natural fibers are beneficial to prepare biodegradable composite materials. A new expression for the Young's modulus of short, natural fiber (SNF) reinforced polymer composites was derived based on a micro-mechanical model. The Young's moduli of poly(lactic acid) reinforced with reed fibers and low-density polyethylene (LDPE) reinforced with sisal fibers, from literature data, were estimated in the fiber weight fraction range from 0 to 50% using the equation and both the compounding rule and the Halpin–Tsai equation, and the estimations were compared with the reported measured data. The results showed that the predictions of the Young's moduli by means of the new Young's modulus equation were close to the measured data from the low density polyethylene/sisal fiber composites, as well as the poly(lactic acid)/reed composites at high fiber concentration. Comparing with other Young's modulus equations, the new Young's modulus equation would be more convenient to use owing to ...

The extrudate swell behavior of polypropylene (PP) composite melts filled with multi-walled carbon nanotubes (MWCNTs) was studied using a capillary rheometer in a temperature range from 190 to 230 degrees C and at various apparent shear rates varying from 50 to 800 s(-1). It was found that the values of the extrudate swell ratio of the composites increased nonlinearly with increasing apparent shear rates, while the values of the extrudate swell ratio decreased almost linearly with increasing temperature. The values of the melt extrudate swell ratio increased approximately linearly with increasing shear stress, while decreased approximately nonlinearly with an increase of the MWCNT weight fraction. In addition, the extrudate swell mechanisms were discussed with observation of the fracture surface of the extrudate using a scanning electronic microscopy. This study provides a basis for further development of MWCNTs reinforced polymer composites with desirable mechanical and thermal properties.

The sound insulation behavior of inorganic hollow microsphere-filled polymer composites was analyzed by means of acoustics theory to reveal the sound insulation mechanisms in the present paper. On the basis of it, a physical model of the sound wave transfer in the composite system was established, and a corresponding sound transmission loss equation was derived. The sound transmission loss ([Formula: see text]) of the hollow glass bead-filled polypropylene composites was estimated by using this equation. The results showed that the calculated sound transmission loss increased linearly with increasing the filler volume fraction, and the values of the [Formula: see text] increased nonlinearly with increasing sound frequency. The sensitivity of the sound transmission loss to sound frequency was significant at low sound frequency. The predicted [Formula: see text] was compared with the measured data from the composites and found that both the estimated [Formula: see text] and the measured data have a similar variation with increasing sound frequency or the filler volume fraction. This study would provide a basis for further development of sound insulation polymer composites.

The flame-retardant properties and impact fracture toughness for the polypropylene (PP) composites filled, respectively, with intumescent flame retardant (IFR) and nanometer calcium carbonate/polyolyaltha olefin were measured in the present paper. It was found that the limited oxygen index increased nonlinearly, whereas the horizontal combustibility rate decreased with increasing the IFR weight fraction (ϕIFR). The smoke density rank increased with increasing ϕIFR. The values of both the V-notched Izod impact strength and Charpy impact strength of the composites were higher than those of the unfilled PP; they decreased slightly with an increase of ϕIFR when ϕIFR was more than 10%. Moreover, the fracture surface of the specimens was observed using a scanning electronic microscope to discuss the mechanisms of the flame retardant and toughening.

The mechanical properties of mesoporous silica (MCM-41) filled poly(l-lactic acid) (PLA4032D) composites and PLA4032D/poly(ethylene glycol) (PEG) composites were investigated. It was found that the Young's modulus increased while tensile strength decreased with increasing the filler content; the V-notched impact fracture strengths of both Izod and Charpy for the PLA4032D/PEG/MCM-41 composites increased while they decreased slightly for the PLA4032D/MCM-41 composites, the unnotched Charpy impact strength of both the two composites decreased with increasing the filler loading; the flexural modulus increased slightly while the flexural strength decreased slightly with increasing the filler content. The toughening mechanisms of the composites were discussed by means of observing the impact fracture surface with a scanning electronic microscope, and the synergistic effect between the PEG and MCM-41 should be one of the major toughening mechanisms. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers

The thermal conductive model of inorganic particulate-filled polymer composites was proposed based on the ANSYS parametric finite element technology, and the numerical simulation of the effective thermal conductivity of low-density polyethylene (LDPE) composite filled with graphite powder was made. It was found that the simulated effective thermal conductivity of the composite increased nonlinearly with an increase of the filler volume fraction, and increased with increasing the particle diameter. Finally, the finite element numerical simulations were compared with the experimental measured data from the LDPE/graphite composite under the same conditions reported in the literature. The results showed that the simulations of the effective thermal conductivity were roughly close to the experimental measured data.

The blends of polylactide (PLA) and poly(ethylene glycol) (PEG) with different contents (0, 5, 10, 15, and 20 wt%) and molecular weights (\( \overline{M}_{w} \) 6000, 10,000 and 20,000, called respectively as PEG 6000, PEG 10,000, and PEG 20,000) were prepared by means of melt blending method. The effects of tensile speed, content and molecular weight of the PEG on the tensile properties of the PLA/PEG blends were investigated using a universal testing machine at 24 °C. With increasing tensile speed, the tensile modulus, strength and stress at break of the PLA/PEG blends marginally increased, while the tensile modulus and stress at break declined non-linearly, and the tensile strength dropped nearly linearly with increasing PEG 10,000 content. When the PEG 10,000 content was 5–15 wt%, the tensile strain at break of the PLA/PEG 10,000 blend markedly increased, and then decreased as the PEG 10,000 content exceeded 15 wt%. With increasing the molecular weight of PEG, tensile modulus and strength increased, whereas the tensile strain at break decreased. This showed that the application of right amount of lower molecular weight PEG was more conducive to improving the tensile toughness of the PLA/PEG blends, which was attributed to its better miscibility with PLA and increased mobility of PLA molecular chains.

The flame retardant and mechanical properties of polypropylene (PP) composites filled with microencapsulated red phosphorus (MRP) and magnesium hydrate (Mg(OH) 2 )/aluminum hydrate (Al(OH) 3 ) were measured. It was found that the synergistic effects between the MRP and Mg(OH) 2 /Al(OH) 3 on the flame retardant and tensile properties of the composites were significant. The limit oxygen index and smoke density rank of the composites increased nonlinearly while the horizontal combustibility rate decreased nonlinearly with increasing the MRP weight fraction. The Young modulus and the tensile elongation at break increased while the tensile yield strength and tensile fracture strength decreased slightly with increasing the MRP weight fraction. Both the V-notched Izod and Charpy impact strength increased with increasing the MRP weight fraction. Moreover, the tensile yield strength of the composites estimated using an equation published previously was roughly close to the measured data.

Polylactide (PLA) was plasticized by polyethylene glycols (PEGs) with five different molecular weights (Mw = 200–20,000 g/mol). The effects of content and molecular weight of PEG on the crystallization and impact properties of PLA were studied by wide-angle X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, transmission electron microscopy, and V-notched impact tests, respectively. The results revealed that PEG-10,000 could significantly improve the crystallization capacity and impact toughness of PLA. When the PEG-10,000 content ranged from 0 to 20 wt%, the increases in both V-notched Izod and Charpy impact strengths of PLA/PEG-10,000 blends were 206.10% and 137.25%, respectively. Meanwhile, the crystallinity of PLA/PEG-10,000 blends increased from 3.95% to 43.42%. For 10 wt% PEG content, the crystallization and impact properties of PLA/PEG blends mainly depended upon PEG molecular weight. With increasing the Mw of PEG, the crystallinity and impact strength of PLA/PEG blends first decreased and then increased. The introduction of PEG reduced the intermolecular force and enhanced the mobility of PLA chains, thus improving the crystallization capacity and flexibility of PLA. Copyright © 2015 John Wiley & Sons, Ltd.

The Polyformaldehyde (POM)/ethylene–vinyl acetate copolymer (EVA)/high-density polyethylene (HDPE) blends and POM/EVA/HDPE composites filled with nanometer calcium carbonate (nano-CaCO3) were prepared using a twin-screw extruder. The effects of the HDPE weight fraction on the flexural and impact properties of the blends and composites were investigated at room temperature. The results showed the flexural modulus and strength of the blends and composites decreased slightly with increasing the HDPE weight fraction. The values of the flexural modulus of the composites were higher than those of the blends, while the values of the impact fracture strength of the blends were higher than those of the composites under the same HDPE weight fraction. This indicated that the impact fracture toughness of the POM could be improved with the HDPE, while the flexural stiffness of the POM blends could be enhanced with the nano-CaCO3 to some extent.

The melt extensional properties of a linear low-density polyethylene (LLDPE) were measured using melt spinning techniques in a range of temperature varying from 150 to 200°C, and the entry flow method in the capillary extrusion at 170°C was used to investigate the effects of elongation strain rate, temperature, and extrusion velocity in the capillary on the melt elongation stress and viscosity. The melt stretching force at break decreased nonlinearly with a rise of temperature. A low melt elongation viscosity might be beneficial to improve the melt drawability. With the increase of elongation strain rate, the melt elongation stress increased while the melt elongation viscosity decreased nonlinearly. Both melt elongation stress and viscosity decreased with a rise of temperature. Under the experimental conditions, the melt elongation stress and viscosity decreased with an increase of extrusion velocity in the capillary. Moreover, the relationship between the elongation viscosity determined from the entry fl...

In order to reduce environmental pollution and recycle the intercalating solution, a new way to prepare expandable graphite (graphite intercalation compound, GIC) by ozone oxidation was proposed. The influences of the intercalating solution, reaction time, ozone flow and concentration of sulfuric acid on exfoliated volume (EV) were discussed in detail. The EV of H2SO4-GIC is much bigger than that of HClO4-GIC or fuming HNO3-GIC. The optimum condition with the maximum EV of 285 ml/g at 950°C may be that reaction time, ozone flow, sulfuric acid concentration are 3.5 hours, 80 ml/min and 98 wt.%, respectively. X-ray diffraction (XRD) patterns were used to analyze the structure and confirmed that GIC had indeed been prepared successfully. Scanning electron microscope (SEM) images showed the morphologies of GIC and exfoliated graphite (EG).

The rheological properties of two kinds of poly (L-lactic acid) melts (AI-1001 and 4032D) have been investigated using a melt flow indexer within the temperature range from 170 to 190 and load varying from 2.16 to 12.5 kg. It was found that the melt volume flow rate (MVR) and extrudate swell ratios (B) increased non-linearly with increasing load when the temperature was constant; the MVR increased while the B decreased with a rise in temperature for both the AI-1001 and 4032D melts; the relationship between the MVR and temperature obeyed expression like as the Arrhenius equation when the load was fixed. Under the same test conditions, the values of the MVR and B of the AI-1001 melt were higher than those of the 4032D melt, and the sensitivity of the MVR and B to the load for the former is higher than those for the latter.

The mechanical properties including tensile, flexural, and impact of the nanometer on calcium carbonate (nano-CaCO3) filled polypropylene (PP)/poly (ethylene-co-octene) (POE) composites were measured at room temperature to identify the effects of the POE content on the mechanical properties. It was found that the Young's modulus, tensile strength, and tensile elongation at break decreased nonlinearly while the tensile fracture strength varied slightly with increasing the POE weight fraction; the V-notched and unnotched Izod impact fracture strength increased nonlinearly with an increase of the POE weight fraction; the flexural modulus and strength decreased roughly linearly with increasing the POE weight fraction. Furthermore, the impact fracture surface of the specimens was observed by means of a scanning electronic microscope to discuss the toughening mechanisms. POLYM. COMPOS., 37:539–546, 2016. © 2014 Society of Plastics Engineers

The sound transmission losses of the three composites including the nanometer calcium carbonate-filled polypropylene (PP/nano-CaCO3) composites, calcium carbonate-filled acrylonitrile butadiene styrene (ABS/CaCO3) composites, and hollow glass bead-filled polyvinyl chloride (PVC/HGB) composites were estimated using the equation of sound transmission loss published previously. The estimated sound transmission losses were compared to the measured data from the sound insulation properties of the three composites measured under the sound frequency varying from 125 to 104 Hz. The results showed that the calculated sound transmission losses were roughly close to the measured data from the three composites under the same conditions, especially in the case of low sound frequency; the values of the sound transmission loss of the PVC/HGB composites were higher than those of the PP/nano-CaCO3 composites and ABS/CaCO3 composites under the same sound frequency, it should be attributed to the extra sound energy consumption was generated in the hollow spheres. POLYM. COMPOS., 2014. © 2014 Society of Plastics Engineers

The effects of the filler content and its surface treatment on the tensile and flow properties of the polypropylene (PP) composites filled with wollastonite (CaSiO3) were investigated. The results showed that the introduction of the filler could reinforce the PP resin, while the influence of the filler surface treatment on the tensile and flow property was insignificant. The melt volume flow rate (MVR) of the composites decreased nonlinearly, while the Young’s modulus increased nonlinearly with increasing filler weight fraction (ϕ w ); the tensile strength and tensile fracture strength increased significantly when ϕ w was ϕ w . The elongation at break decreased significantly when ϕ w was ϕ w . Moreover, the Young’s modulus was estimated using the equation published earlier, and a good agreement was shown between the predicted data and the measured data.

The V-notched Izod impact strength of poly-L-lactide composites filled with nanosized calcium carbonate was measured at room temperature. The fractal dimensions of the impact fracture surface were determined by means of the structure function method, and the relationship between the measured impact strength and the fractal dimensions of the specimen fracture surface was investigated. The results showed that the fractal dimensions of the fracture surface were within the range of about 1.76 to 1.97, all of the correlation coefficients were higher than 0.9, the strong linear correlation indicated that the fractal characterization of the fracture surface for the composites was significant, the measured impact strength increased obviously with increasing fractal dimension of the fracture surface and the correlation between them was roughly linear when the fractal dimension was more than 1.88.

The effects of nanometer calcium carbonate content and tensile rate on the tensile properties of the filled polycaprolactone (PCL) composites were investigated. There was a certain reinforcing effect of the filler on the PCL resin. The tensile modulus increased nonlinearly, and the tensile strength also increased with increase of the filler weight fraction. When the filler weight fraction was kept constant, the tensile modulus and tensile strength increased slightly with increasing tensile rates. By comparing the experimental results with those determined from the tensile yield strength theory, the interfacial adhesion between the filler and matrix was found to be relatively strong; it should be one of the reasons for the good reinforcing effect.

The effects of the microencapsulated red phosphorus (MRP) content and specimen thickness on the mechanical properties of the filled polypropylene (PP) composites were studied at room temperature. The results showed that the influence of the MRP on the tensile and impact properties of the composites was significant, and the Young's modulus and impact strength of the composites increased nonlinearly while the tensile strength decreased slightly with increasing the MRP weight fraction; the tensile elongation at break increased outstandingly when the MRP weight fraction was less than 2% and then decreased with increasing the MRP weight fraction. Furthermore, the impact fracture surface was examined by scanning electronic microscope. The results suggested that the toughening effect was attributed to the absorption of impact fracture energy by the microencapsulated layer. Copyright © 2014 John Wiley & Sons, Ltd.

Shear and extensional properties of high-density polyethylene (HDPE) and poly(butylene succinate) (PBS) blends were measured using capillary rheometers to investigate the influences of processing conditions and mixing ratios on flow behaviors, and the predictive abilities of extensional master curve, back propagation neural network model, and constitutive equation were analyzed for the extensional flow. The results showed that the shear flow of blend melts obeyed the power law, and the influence of PBS content on shear-thinning behavior was obvious. The extensional viscosity of the blends decreased with extensional strain rate, extrusion rate, and PBS content increasing. The extensional master curve was applied for HDPE/PBS blends, and scaling factor reduced with the increasing extrusion rate. In addition, the approach of back propagation neural network model was an effective approach to predict extensional viscosity for the purposes of polymer processing control and monitoring.