Regulation Of Polymer On Calcium Oxalate Urinary Calculi Grown In Aqueous Solutions

Studies on the effect of polyacrylamide and differernt molecular weight of polyethylene glycol(PEG) on the phase compositions of calcium oxalate crystals were investigated by means of X-ray powder diffraction(XRD), scanning electron microscopy(SEM) and atomic absorptin spectrum(AAS). the effect of the concentration of these polymers, pH, calcium/oxalate stoichiometrical ratio and the different initial CaOxa supersaturation on the crystallization ofcalcium oxalate ware discussed.Polyacrylamide(PAM) promoted the formation of calcium oxalate dihydrate(COD), changed morphology of calcium oxalate monohydrate(COM) crystals and calcium oxalate dihydrate (COD) crystals, inhibited the nucleation of COM, however, promoted the aggregation and growth of COM crystals. The larger value of calcium/oxalate stoichiometrical ratio was, more easyly promoted the formation of dumbbell-shaped COD crystals. The larger value of pH was, the more number of COD crystals was. Calcium oxalate crystals with various phase and morphologies could be prepared by changing the experimental conditions.Comparative study on the effect of four kinds of PEG(PEG-400, PEG-4000, PEG-6000, and PEG-12000) on the phase composition of calcium oxalate crystals was investigated. The smaller molecular weight of polyethylene glycol inhibited calcium oxalate crystals more stronger, and with molecular weight of PEG increased, the inhibitor decreased; As the concentration of PEG increased, the structure of PEG was transferred from chain link to crown ether, so the inhibitor was changed by PEG structure; As initial CaOxa supersaturation increased, the size of CaOxa crystals was decreased, and the polymerization degree of crystals was low.