Biomimetic Synthesis Of Calcium Carbonate Using Organic Matrix And Study Of PVC Modified With It

Calcium carbonate (CaCO₃) is one kind of widely used inorganic filler with low-cost, excellent reinforcing effect, high gloss and low wearabiligy. CaCO₃ can effectively reduce the cost, improve the mechanical properties and the appearance of the products. Currently, CaCO₃ has been widely used in plastic, rubber, papermaking, coatings, printing ink et.. As widely used inorganic filler, the poor compatibility of CaCO₃ with polymers restricts its extensive application. In this work, CaCO₃ was synthesized by a biomimetic method to achieve crystals with different shape. The synthesized CaCO₃ were applied to polyvinyl chloride (PVC) to improve its mechanical properties. Research the influence of calcium carbonate using organic matrix for the mechanical properties of PVC, and comparative with the ordinary CaCO₃, explore the former method for PVC synthesis if better than that of the latter or not, and reveals its mechanism.Part I: for the biomimetic synthesis of CaCO₃, sodium dodecyl benzene sulfonate (SDBS), glycol, polyvinyl alcohol (PVA) and polyethylene glycol 400 (PEG-400) were used as the organic templates, respectively. Three methods were used to synthesize CaCO₃: metathesis method, urea hydrolysis method and cabonization method, last we character them with scanning electron microscope, fourier transform infrared spectroscopy, X-ray powder diffraction. The results show that the crystal morphology of CaCO₃ changes a lot, we get spindle-shaped CaCO₃ by metathesis method; regular hexagon, slightness bar, flower shape CaCO₃ by urea hydrolysis method; irregular square block by cabonization.Part II: The synthesized CaCO₃ by biomimetic method were applied to PVC, and the tensile properties and impact strength were characterized. (1) Compared with the addition of commercial used CaCO₃, the addition of CaCO₃ significantly improved the tensile strength, the elongation at break and impact strength. The tensile strength reached the maximum at loading of 5 10%. At the same amount (5%) of CaCO₃, the tensile strength was improved by 12% for the SDBS modified CaCO₃ than the common CaCO₃. When the CaCO₃ loading is 10%, the tensile strength was improved by 12% for the SDBS/glycol modified CaCO₃ added system than the original CaCO₃ one. When the CaCO₃ loading is 20%, the tensile strength was improved by 11% for the glycol modified CaCO₃ added system than the original CaCO₃ one. (2) The elongation at break was improved by 115% for the biomimetic synthesized CaCO₃ . (3) For the impact strength, after the addition of SDBS and SDBS/glycol modified CaCO₃, the impact strength is beyond the range of the impact machine, indicating the high toughness.