Abrasion due to the high speed mixing of rigid PVC dry blends filled with CaCO3 was found to be a function of both the mixing conditions and type and level of CaCO3 used. Laboratory scale tests showed that abrasion is a function of mix time, mix speed, and mixer blade geometry. These variables were standardized to develop a laboratory abrasion test using a Hockmeyer mixer equipped with a soft 3-in diameter aluminum mixing blade. This procedure was used to investigate the effect of CaCO3 property variables on abrasion during rigid PVC dry blending. Multiple linear regression analysis at 30 phr CaCO3 showed that abrasion increased with filler top cut, mean, acid insolubles, and MgCO3 content, but diminished with an increase in percent less than 1 micron fraction. A more generalized abrasion predictor model was developed by considering surface area to be a linear function of top cut, mean, and percent less than 1 micron properties. Abrasion was greatly minimized by using finer particle size, higher surface area CaCO3 with low acid insoluble and magnesium carbonate levels. These criteria also aid in reducing the abrasive effects of TiO2 during dry blending through a CaCO3/TiO2 interaction. 相似文献
Disposable PVC gloves are cost effective, but their mechanical properties can be compromised at extremely high concentrations of plasticizers. The tensile properties of PVC gloves can be improved by incorporating modified fillers into the PVC matrix. In this research, calcium carbonate (CaCO3) was functionalized with γ-methacryloxy propyl trimethoxyl silane (KH-570) and then further modified through a click reaction with n-Octadecyl mercaptan. Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy have confirmed that n-Octadecyl mercaptan-modified KH-570 was successfully grafted onto the surface of CaCO3. Composite films were manufactured by blending either pristine CaCO3 or modified CaCO3 with PVC resin paste and their tensile properties, light transmission, moisture permeability, and solvent resistance were evaluated. Compared with CaCO3/PVC and KH-570-modified CaCO3/PVC composite films, n-Octadecyl mercaptan-modified CaCO3/PVC composite films showed higher light transmittance, lower moisture permeability, and higher tensile properties. Dynamic mechanical analysis revealed that these films had low glass transition temperatures, thus broadening their applicability to low-temperature conditions. 相似文献
Calcium carbonate (CaCO3) is the most commonly used inorganic filler in polymer materials to improve the mechanical properties and reduce the costs. However, there are few reports on the preparation of cooling materials using CaCO3. In this study, CaCO3 was introduced into the polymer matrix as a solar reflective filler to prepare passive cooling materials. Specifically, the influences of CaCO3 content on the structure and performances of polyvinyl chloride (PVC)/CaCO3 composite films were characterized by scanning electron microscope (SEM), contact angle test, surface roughness and glossiness, solar reflectivity, thermal emissivity, temperature test and mechanical property characterization. When the volume fraction of CaCO3 reaches 67%, the total solar reflectance of PVC/CaCO3 composite films is 80.8%, which is 351.4% higher than that of PVC films. CaCO3 powder has little influence on the thermal emissivity of the atmospheric window (3-5 μm and 8-13 μm) of the composite films, which remains at a high level about 0.86. In temperature test, the final temperature of sample 67 v% is only 26.8°C, which is only 2.8°C higher than the room temperature and 22.2°C lower than that of PVC films. For comparison, the cooling performance of PVC/titanium dioxide (TiO2) composite films with 10 v% TiO2 was also measured, and the final temperature is 29.1°C, even 2.3°C higher than that of PVC/CaCO3 composite films with 67 v% CaCO3. In this study, the cost-effective and solar-reflective PVC/CaCO3 composites have potential application in cooling material field. 相似文献
Poly(vinyl chloride) (PVC)/calcium carbonate (CaCO3) nanocomposites were synthesized by in situ polymerization of vinyl chloride (VC) in the presence of CaCO3 nanoparticles. Their thermal, rheological and mechanical properties were evaluated by dynamic mechanical analysis (DMA), thermogravimetry analysis (TGA), capillary rheometry, tensile and impact fracture tests. The results showed that CaCO3 nanoparticles were uniformly distributed in the PVC matrix during in situ polymerization of VC with 5.0 wt% or less nanoparticles. The glass transition and thermal decomposition temperatures of PVC phase in PVC/CaCO3 nanocomposites are shifted toward higher temperatures by the restriction of CaCO3 nanoparticles on the segmental and long-range chain mobility of the PVC phase. The nanocomposites showed shear thinning and power law behaviors. The ‘ball bearing’ effect of the spherical nanoparticles decreased the apparent viscosity of the PVC/CaCO3 nanocomposite melts, and the viscosity sensitivity on shear rate of the PVC/CaCO3 nanocomposite is higher than that of pristine PVC. Moreover, CaCO3 nanoparticles stiffen and toughen PVC simultaneously, and optimal properties were achieved at 5 wt% of CaCO3 nanoparticles in Young's modulus, tensile yield strength, elongation at break and Charpy notched impact energy. Detailed examinations of micro-failure micromechanisms of impact and tensile specimens showed that the CaCO3 nanoparticles acted as stress raisers leading to debonding/voiding and deformation of the matrix material around the nanoparticles. These mechanisms also lead to impact toughening of the nanocomposites. 相似文献
The influence of thermodynamic interactions among the components of a polymer system on mechanical properties and their retention on aging has been investigated. The systems considered involve plasticized poly(vinyl chloride)(PVC), and CaCO3 fillers. Inverse gas chromatography was used to measure interaction parameters, and to express these in terms of acid-base concepts. Interaction data were obtained over a wide temperature range. It was shown that the volume of plasticizers retained by the PVC correlates with the measured interaction parameters. Similarly, the interaction parameters identify a CaCO3 filler preferred for reinforcing rigid PVC, and a different CaCO3 filler for use in given PVC-plasticizer combinations. The mechanical properties of filled PVC (up to 40 phr CaCO3), and particularly the ultimate properties of the compounds, correlate with interaction concepts, as do property retention data after accelerated aging of the compounds at 100°C. It is concluded that component interaction parameters may provide useful guidelines to the formulation of compounds with superior properties and reduced property losses due to aging. 相似文献
Summary: The effects of interfacial interaction between nano‐CaCO3 and PVC on mechanical properties and morphology of PVC/nano‐CaCO3 composites were studied. Nano‐CaCO3 was treated with vibromilling in the presence of PVC and coupling agents. The mechanical properties of PVC/treated nano‐CaCO3 are remarkably improved. Transmission electron microscopy results revealed that vibromilled nano‐CaCO3 particles are well dispersed in PVC matrix with good homogeneity and well adhered to PVC matrix. Molau test indicated that chemical reaction between newly formed surface of nano‐CaCO3 and PVC or coupling agent took place. Theoretical calculation results show that the interfacial interaction between PVC and nano‐CaCO3 are substantially improved through vibromilling treatment of nano‐CaCO3 in the presence of PVC and coupling agent.