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1.
Biaxial stretching of polypropylene sheets containing CaCO3 filler results in microporous sheets, that feel soft and dry. Their properties depend on filler content, particle size of the filler, and stretching degree etc. We have studied the dependency of some properties of the microporous polypropylene sheets on stretching degree. It is elucidated that mechanical properties are controllable by adjusting stretching degrees in machine and transverse directions. © 1993 John Wiley & Sons, Inc.  相似文献   

2.
Microporous polypropylene sheets are prepared by biaxially stretching polypropylene sheets containing CaCO3 filler. Here, the stretching ratio is one of the most important factors in the preparative process, and removing the CaCO3 filler also affects the sheet properties. Their effects were studied in relation to the properties and the structure of the microporous polypropylene sheets. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1543–1553, 1998  相似文献   

3.
Microporous polypropylene hollow fibers with double layers were prepared by stretching double layered polypropylene microtubes containing polymethylsilsesquioxane fillers: the relatively smaller filler in the inner layer and relatively larger filler in the outer layer. The resultant hollow fibers have a finely interconnected fibrous structure parallel to fiber axis. Their N2 gas permeabilities were measured to estimate the fibrous structure: tortuosity factor, effective porosity, and pore size. © 1995 John Wiley & Sons, Inc.  相似文献   

4.
Calcium carbonate (CaCO3) reinforced polypropylene/ethylene propylene rubber (PP/EPR) copolymer composites for automotive use were developed by means of extrusion and injection molding process. Three kinds of CaCO3 (stearic acid treated and untreated) nanoparticles and microparticles were used as fillers. The influence of stearic acid, particle size, and filler content on the state distribution and morphology were investigated by SEM and rheological measurements. Two different morphologies were observed: EPR and CaCO3 dispersed in the PP matrix and a core shell structure, depending on the interactions between EPR and CaCO3. Toughening mechanisms and mechanical properties of the different systems were investigated. Significant improvement in tensile modulus is observed in all composites, depending on filler content. Elongation and notched impact strength were drastically decreased, especially for composites with nano CaCO3. Better impact properties were obtained with low content of treated particles, showing the importance of filler treatment. POLYM. ENG. SCI., 55:2859–2868, 2015. © 2015 Society of Plastics Engineers  相似文献   

5.
Microporous polypropylene sheets were prepared as follows. First, polypropylene pellet-containing CaCO3 filler was extruded to prepare base sheets, which were then biaxially stretched. The draft effect at the extrusion process was studied in relation to some properties of the resultant microporous polypropylene sheets. © 1996 John Wiley & Sons, Inc.  相似文献   

6.
Influence of filler size on impact properties for polypropylene (PP)/elastomer/filler ternary composites was investigated. Calcium carbonate (CaCO3) particles with a diameter in the range from 120 to 1200 nm were used as a filler and polystyrene-block-poly(ethylene-butene)-block-polystyrene triblock copolymer (SEBS) was used as an elastomer. In the PP/SEBS/CaCO3 ternary composite, CaCO3 particles and SEBS particles were dispersed in the PP matrix separately. In the case that SEBS elastomer volume fraction was below 0.12, the impact strength improved gradually with a decrease of CaCO3 mean diameter from 1200 to 160 nm. In the case that SEBS volume fraction was above 0.17, the impact strength improved significantly by the incorporation of CaCO3 particles with a mean diameter in the range from 120 to 900 nm. However, the impact strength hardly improved by the incorporation of CaCO3 particles with a mean diameter of 1200 nm.  相似文献   

7.
Coal gasification fine slag glass beads (CGFSGBs) were processed via an efficient pneumatic separation technique. CGFSGB products (CGFSGB-S1, CGFSGB-S2, and CGFSGB-S3) with different sizes were acquired. The heavy calcium carbonate (CaCO3) was used as comparative filler. Effects of particle size and geometric shape on mechanical strengths, flow properties, and solid density of filled acrylonitrile–butadiene–styrene (ABS) were investigated. The mechanical strengths of composites decreased with increasing CGFSGB weight fraction, while MFR and solid density increased. The mechanical strengths were found to increase with decreasing CGFSGB size, and spherical surface of the CGFSGB is more beneficial to improve interface adhesion strength than square surface of the CaCO3. The flow property analysis showed that the ABS/CaCO3 composites have better fluidity and the advantages in the processing energy consumption. However, the incorporation of CaCO3 resulted in the higher solid-state density. In summary, CGFSGBs have the potential to replace CaCO3 in the ABS market. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48601.  相似文献   

8.
Three types of polypropylene (PP) with different intrinsic toughness were used to study the mechanical properties and morphologies of the PP composites filled with single‐filler and hybrid‐filler of calcium carbonate particles. The calcium carbonate particles used were with average particle sizes of 25 μm (CC25), and 0.07 μm (CC0.07), respectively. A hybrid‐filler CaCO3 named CC25/CC0.07 was used as a mixture of CC25 and CC0.07 (CC25/CC0.07 weight ratio = 1:1). It was found that the type of PP and the particle size of inorganic filler were the two important factors for the determination of mechanical properties of the composites. And the general mechanical properties of the composites filled with hybrid‐filler CaCO3 were better than those of the composites filled with single‐filler CaCO3, but the synergistic hybridization effect of the hybrid‐filler CaCO3 did not exist. The major toughening mechanism of the PP/CC25 composites was the cavitation of the matrix caused by CC25, and the major toughening mechanism of the PP/CC0.07 composites was the pinning effect introduced by CC0.07. For the PP/CC25/CC0.07 composites, the cavitation of the matrix caused by CC25 and the pinning effect introduced by CC0.07 existed simultaneously. And when the intrinsic toughness of the matrix was large enough, the major factor to toughen PP was the pinning effect introduced by CC0.07, otherwise the major factor to toughen PP was the cavitation of the matrix caused by CC25. POLYM. ENG. SCI., 47:95–102, 2007. © 2007 Society of Plastics Engineers  相似文献   

9.
Polypropylene (PP)/elastomer/fine filler particle ternary composite was prepared using polystyrene-block-poly(ethylene-butene)-block-polystyrene triblock copolymer (SEBS) or carboxylated SEBS (C-SEBS) as elastomer and calcium carbonate (CaCO3) having mean size about 160 nm as filler. First, SEBS (or C-SEBS) and CaCO3 particles were mixed to form master batch. Second, the prepared master batch and PP matrix were kneaded. In the PP/SEBS/CaCO3 ternary composite, CaCO3 particles and SEBS particles were dispersed in the PP matrix separately. In the PP/C-SEBS/CaCO3 ternary composite, CaCO3 particles were encapsulated in C-SEBS and formed a core–shell structure at lower CaCO3 concentration; however, some CaCO3 particles were dispersed in PP matrix at higher CaCO3 concentration. In the PP/SEBS/CaCO3 composite, the impact strength increased with the amount of incorporated CaCO3 particles. Whereas, in the PP/C-SEBS/CaCO3 composite, the impact strength increased with the amount of CaCO3 particles dispersed in PP matrix. The master-batch method was found to be useful for improving the dispersibility of CaCO3 particles than the commonly used single-batch method.  相似文献   

10.
The rheological properties of silicone sealant filled with different calcium carbonate (CaCO3) particles varying in size were investigated. It is found that as particle size decreases, the dynamic storage modulus (G′) and shear viscosity (η) increase; whereas, the width of linear viscoelastic region decreases. At low shear rate, a modulus plateau appears and the shear thinning behavior becomes apparent. The reasons for these can be ascribed to the enhanced particle–particle interaction and formation of filler network structure. Moreover, results dealing with the buildup of network structure monitored by kinetic recovery experiments reveal that both the rate of recovery and magnitude of rheological parameters increase with decreasing particle size. This phenomenon is consistent with the data collected from creep and recovery measurements, indicating an enhanced elasticity and network structure. Furthermore, transmission electron microscopy (TEM) observation and mechanical properties tests for cured sealant samples were also carried out to provide an evidence for the discussion further. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers  相似文献   

11.
Tensile and impact behavior of CaCO3-filled polypropylene was studied in the composition range 0–60 wt % filler. Tensile modulus increased while tensile strength and breaking elongation decreased with increase in CaCO3 content. The modulus increase and elongation decrease were attributed to increased filler–polymer interaction resulting in reduction in molecular mobility, while increased amorphization and obstruction to stress transfer accounted for the tensile strength decrease. Analysis of tensile strength data showed introduction of stress concentration in the composites. Izod impact strength at first increased up to a critical CaCO3 content, beyond which the value decreased. Surface treatment of CaCO3 with a titanate coupling agent LICA 12 enhances the adhesion of the filler and polymer, which further modifies the strength properties. Scanning electron microscopic studies indicated better dispersion of CaCO3 particles upon surface treatment, which effected the changes in the strength properties of the composites.  相似文献   

12.
《国际聚合物材料杂志》2012,61(3-4):205-222
Abstract

Investigation of crystallization behaviour of isoatactic polypropylene (i-PP) in i-PP/CaCO3 composites is carried out through Differential Scanning Calorimetry (DSC) and wide angle X-ray diffraction measurements. The effect of CaCO3 and its surface treatment with titanate coupling agent on nucleation and growth rate of crystallization, crystallite size distribution and crystallinity, is determined from exothermic crystallization peaks of the composites. The filler concentration dependence of crystallinity determined by both the techniques shows good qualitative agreement. Tensile properties viz. tensile modulus, yield stress and elongation were also measured as functions of filler concentration for both untreated and treated CaCO3 filled composites. Crystallinity, tensile strength and elongation decreased with increasing filler content in both the cases whereas tensile modulus increased. Crystallization parameters have been correlated with the tensile properties of i-PP/CaCO3 composites.  相似文献   

13.
A complex of trivalent lanthanum stearate with stearin (REC) was used as a surface modifier to treat calcium carbonate, and its efficacy was assessed. The measurement of the viscosity of a CaCO3/liquid paraffin suspension demonstrated that REC treatment could considerably improve the dispersion of filler in nonpolar media. The FTIR spectrum analysis revealed that the REC bonded to the CaCO3 surface not only by physical absorption but also by a chemical reaction. The REC could change the surface properties of CaCO3, resulting in greater hydrophobicity of the surface and enhanced compatibility with nonpolar matrices. The mechanical properties and melt flow rate (MFR) examination of polypropylene (PP)/CaCO3 composites showed that REC treatment remarkably enhanced the toughness and MFR of composites at higher filler loading. The fractured surface observation with SEM showed improved filler dispersion and enhanced interfacial adhesion between the filler and matrix in PP composites filled with REC‐treated CaCO3. All these improvements demonstrated that REC is an effective surface modifier of CaCO3. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1339–1345, 2001  相似文献   

14.
Toughening of polypropylene with calcium carbonate particles   总被引:4,自引:0,他引:4  
Polypropylene-CaCO3 composites were prepared on a twin screw extruder with a particle content of 0-32 vol%. The influence of particle size (0.07-1.9 μm) and surface treatment of the particles (with and without stearic acid) on the toughening properties were studied. The matrix molecular weight of the polypropylene was also varied (MFI 0.3-24 dg/min). The experiments included tensile tests, notched Izod impact tests, differential scanning calorimetry (DSC), scanning electron microscopy and rheology experiments. The modulus of the composites increased, while the yield stress was lowered with filler content. This lowering of yield stress was connected to the debonding of the particles from the polypropylene matrix. From DSC experiments it was shown that the particle content had no influence on the melting temperature or crystallinity of the PP phase, also particle size showed no effect on the thermal properties. The impact resistance showed large improvement with particle content. The brittle-to-ductile transition was lowered from 90 to 40 °C with the addition of CaCO3 particles. Notched Izod fracture energy was increased from 2 up to 40-50 kJ/m2. The stearic acid coating on the particle surface showed a large positive effect on the impact strength. This was mainly due to the improved dispersion of the CaCO3 particles. Aggregates of particles clearly had a detrimental effect on the impact behaviour of the composites. The smaller particle sizes (<0.7 μm) showed coarse morphologies and this lowered the toughening efficiency. The molecular weight of the polypropylene matrix had a profound effect on the toughening properties. A higher molecular mass shifted the brittle-to-ductile transition towards lower temperatures. At the higher filler loads (>20 vol%), however, still problems seem to occur with dispersion, lowering the toughening efficiency. Of all particle types used in this study the stearic acid treated particles of 0.7 μm were found to give the best combination of properties. From the study of the micro-toughening mechanism it was shown that at low strain the particles remain attached to the matrix polymer. At higher strain the particles debond and this leads to a change in stress state at the particle size level. This prevents crazing of the matrix polymer and allows extensive plastic deformation, resulting in large quantities of fracture energy.  相似文献   

15.
The effects of filler particle size and concentration on the rheological properties of hydroxyl terminated polydimethylsiloxane (HO‐PDMS) filled with calcium carbonate (CaCO3) were investigated by an advanced rheometric expansion system (ARES). The Casson model was used to describe the relationship between shear stress and shear rate for steady‐state measurement. Micron‐CaCO3 could not afford the CaCO3/HO‐PDMS suspensions obvious shear thinning behavior and a yield stress high enough, whereas nano‐CaCO3 could provide the suspensions with remarkable shear thinning behavior and high yield stress. Incorporation of nano‐CaCO3 into HO‐PDMS resulted in the transformation of HO‐PDMS from a mainly viscous material to a mainly elastic material. With increasing nano‐CaCO3 content, shear thinning behavior of nano‐CaCO3/HO‐PDMS suspensions became more obvious. Remarkable yield stress was observed in nano‐CaCO3/HO‐PDMS suspensions with high filler content, and increased with increasing nano‐CaCO3 content. The degree of thixotropy was quantitatively determined using a thixotropic loop method. It was found that nano‐CaCO3 favored more the buildup of filler network structure in the suspensions than micron‐CaCO3 at the same weight fraction. Furthermore, increasing nano‐CaCO3 content accelerated the establishment of filler network structure in the nano‐CaCO3/HO‐PDMS suspensions. An overshoot phenomenon was observed in the nano‐CaCO3/HO‐PDMS suspensions at high shear rates. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3395–3401, 2006  相似文献   

16.
The effects of calcium carbonate (CaCO3) particle size on the fusion and rheological behaviors of rigid poly(vinyl chloride) (PVC) composites prepared in a Haake torque rheometer were investigated by means of torque data recorded during processing. Increasing the number of particles in the same blend volume by decreasing the particle size resulted in increasing frictional forces. This increase led in turn to increased fusion torque and decreased fusion time and temperature. The power‐law‐index values of the composites increased with decreasing particle size except for 25‐nm CaCO3. The viscosities of all composites were found to decrease with shear rate; therefore, high pseudoplasticity was observed. At a particular rotor speed, viscosity of the composites decreased with decreasing particle size except for 25‐nm CaCO3. The overall results showed that the particle size of CaCO3 altered the fusion characteristics and rheological behavior of PVC. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers  相似文献   

17.
In order to improve the β‐lamellae distribution and properties of β‐isotactic polypropylene (β‐iPP) membranes, amounts of 5 and 10% active nano‐CaCO3 were added into β‐iPP. Differential scanning calorimetry, X‐ray diffraction and scanning electron microscopy results show that nano‐CaCO3 does not reduce the content of β‐crystals, but the thickness, lamellae thickness distribution and stability of β‐lamellae decrease apparently. Tensile testing was conducted at 25 and 90 °C. The results manifest that the second yield point, which has a strong negative correlation with lamellae thickness distribution, is delayed monotonically with addition of nano‐CaCO3 when stretched at 25 °C, indicating that nano‐CaCO3 could narrow effectively the lamellae thickness distribution of β‐iPP. Furthermore, when stretched at 90 °C, the subdued yield peak, retarded necking‐down phenomenon and enhanced strain‐hardening modulus demonstrate that the deformation stability improves gradually with introduction of nano‐CaCO3, which is completely opposite to the trend for β‐lamellae stability. Through further detailed characterization of morphological evolutions during stretching, we found that interfacial debonding between nano‐CaCO3 and β‐iPP is triggered and abundant microviods can be formed, which can retard the rotation and slip of β‐lamellae and make the βα transformation slow down in the initial stage of stretching, consequently leading to better isotropic deformation. Moreover, nano‐CaCO3 could efficiently restrain the formation of coarse fibrils, leading to more uniform pore size distribution within the biaxial stretching microporous membrane. However, excessive nano‐CaCO3 (10%) would cause aggregation within the β‐iPP cast film and finally result in larger pores and poor pore distribution in the membrane. © 2017 Society of Chemical Industry  相似文献   

18.
Calcium carbonate‐filled syndiotactic poly(propylene) (CaCO3‐filled s‐PP) was prepared in a self‐wiping, co‐rotating twin‐screw extruder. The effects of CaCO3 of varying particle size (1.9, 2.8 and 10.5 μm), content (0–40 wt %), and type of surface modification (uncoated, stearic acid‐coated, and paraffin‐coated) on the crystallization and melting behavior, mechanical properties, and processability of CaCO3‐filled s‐PP were investigated. Non‐isothermal crystallization studies indicate that CaCO3 acts as a good nucleating agent for s‐PP. The nucleating efficiency of CaCO3 for s‐PP was found to depend strongly on its purity, type of surface treatment, and average particle size. Tensile strength was found to decrease, while Young's modulus increased, with increasing CaCO3 content. Both types of surface treatment on CaCO3 particles reduced tensile strength and Young's modulus, but improved impact resistance. Scanning electron microscopy (SEM) observations of the fracture surfaces for selected CaCO3‐filled s‐PP samples revealed an improvement in CaCO3 dispersion as a result of surface treatment. Finally, steady‐state shear viscosity of CaCO3‐filled s‐PP was found to increase with increasing CaCO3 content and decreasing particle size. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 201–212, 2004  相似文献   

19.
The results of a study of the relation between the oriented structure and drawn Poly(ε‐caprolactone) specimens including CaCO3 particles and their dynamic mechanical properties are presented. The loss elasticity, E″, showed almost the same curve for both undrawn sheets and drawn sheets as a function of CaCO3 content. On the other hand, the storage modulus, E′, of drawn sheets increased nonlinearly with increasing CaCO3 content, and their curve showed lower E′ values than those of undrawn sheets. By simulation of 13C CP NMR spectra of drawn PCL/CaCO3 sheets, both oriented and unoriented components were observed. The distribution parameter, p, of drawn PCL/CaCO3 sheets was 13°, which was larger than those (8°) of drawn PCL. Further, the fraction of the unoriented component increased with increasing CaCO3 content. Thus, adding CaCO3 particles into the PCL, the arrangement of the oriented component was disturbed and decreased. In addition, from the line shape analyses of 13C CP MAS NMR spectra, four peaks were obtained in not only undrawn sheets but also in drawn sheets of both PCL and PCL/CaCO3 compounds. Besides, structural change occurred at only drawn PCL/CaCO3 sheets. Therefore, the change in dynamic mechanical properties observed only for drawn PCL/CaCO3 sheets were strongly dependent on the orientational structure, which was formed under shear stress of the stretching drawn process. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2376–2382, 2001  相似文献   

20.
Steady‐state and oscillatory shear behavior of three neat syndiotactic polypropylene (s‐PP) resins and a s‐PP resin (s‐PP#8) filled with CaCO3 particles of varying content, size, and type of surface modification were investigated. All of the neat s‐PP resins investigated exhibited the expected shear‐thinning behavior. Both the storage and loss moduli increased with decreasing temperature. The shift factors used to construct the master curves were fitted well with both the Arrhenius and the Williams–Landel–Ferry (WLF) equations. The inclusion of CaCO3 particles of varying content, size, and type of surface modification, to a large extent, affected both the steady‐state and oscillatory shear behavior of s‐PP/CaCO3 compounds, with the property values being found to increase with increasing content, decreasing size, and surface coating of the CaCO3 particles. Lastly, the effects of melt‐annealing and crystallization temperatures on isothermal crystallization behavior of s‐PP#8 filled with CaCO3 particles of varying content, size, and type of surface modification were also investigated. The half‐time of crystallization of neat s‐PP#8 exhibited a strong correlation with the choice of the melt‐annealing temperature (Tf) when Tf was less than about 160 °C, while it became independent of Tf when Tf was greater than about 160 °C. On the other hand, the half‐time of crystallization of s‐PP#8/CaCO3 compounds did not vary much with the Tf. Generally, the observed half‐time of crystallization decreased with increasing CaCO3 content and increased with increasing CaCO3 particle size. Finally, coating the surface of CaCO3 particles with either stearic acid or paraffin reduced the ability of the particles to effectively nucleate s‐PP#8. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4515–4525, 2006  相似文献   

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