Research On The Surface Functionalization Of Biomass Calcium Compound And Its Application In Filled Polypropylene

In our daily lives, we inevitably meet many kinds of waste biomass calcium compounds,such as eggshell, shell, and bone. The biomass calcium compounds are generated in acomplicated biological process. Despite higher purity and finer structure than natural mineralcalcium, they have not been attracted significant attention for research and usage. Therefore, thisthesis offers a new resource way for application of biomass calcium compounds. The wastebiomass calcium compounds were treated through surface modification or heat treatment for thecalcification of particles with β-nucleating ability to polypropylene (PP), to be used as fillers tomake PP composites. In this thesis, the resource modification technology of waste biomasscalcifications and its application in PP composites were studied.1. The preparation process and structure of PP composites with natural and modified shellpowder with pimelic acid were studied. The results indicated the natural shell powder hasobvious heterogeneous nucleation effect on PP and provides β nucleating capacity to somedegrees. Through modification with pimelic acid, the natural shell powder revealed as a kind of βnucleating agent consisting of pimelic acid salt on its surface with obvious β nucleating capacityto PP. With the addition of modified natural shell powder to PP, the impact toughness and at thesame time the rigidity were significantly improved.2. The β nucleation mechanism of Monetaria moneta with high β nucleating capacity to PPwas studied. As a result of heat treatment to Monetaria moneta, the organic matter contents andthe crystal structure of the calcium carbonate in the shell were changed. The results show thatwith heat treatment of shells below360°C, the crystal structure of calcium carbonate inMonetaria moneta kept the aragonite structure with β nucleating capacity to PP. Treatment atabove400°C changed the aragonite crystal structure of calcium carbonate in Monetaria monetato calcite structure without β nucleating capacity to PP. The β nucleation mechanism ofMonetaria moneta with high β nucleating capacity to PP is due to the crystal cell parameters ofthe aragonite in Monetaria moneta as similar to that of β-PP, and the organic matter play no rolein this phenomenon.3. The influence of natural shell powder on the crystallization kinetics of PP was studied.As heterogeneous nucleating agent, the natural shell powder has α and β nucleating capacity toPP. With little addition, the shell powder could promote the crystallization of PP. With increasing to a certain amount, the shell particles agglomerate, making the unique structure with small βnucleating capacity to PP.4. The preparation process and structure performance of the PP composites with natural andmodified eggshell with pimelic acid were studied. The results show that the eggshell powderwith high content of organic matter has nearly no heterogeneous nucleation effect to PP, butcould induced a small amount of β crystal structure. After surface treatment with pimelic acid,the eggshell powder revealed a very strong β nucleating capacity and a good compatibility withPP, providing good balance in rigidity and toughness to PP composites.5. The structure of PP composites with pig bone powder and the effects on the productionof β-PP composites were studied. With the same component, the bone powder revealed lessnucleating capacity in acting as β nucleating agent. Because of the low rigidity of calciumphosphate in the bone powder and because the agglomeration phenomenon was serious, theoverall mechanical properties of PP composites with this filler decreased.6. In order to improve the compatibility between the inorganic particles with β nucleatingcapacity and PP, grafting of monomers with coupling effect and β nucleating capability wereinduced on the surface of the calcium carbonate. The crystalline structure and mechanicalperformance of the PP composites and their relationships were studied. The results show that thegrafting reaction could limit the moving of the PP chains around the calcium carbonate. Duringthe cooling stage, the PP chains could contact with β nucleating agent, increasing the content ofβ-PP. The grafting reaction improved the compatibility between filler and PP matrix, improvingthe toughness of the products.7. The polyamide-6(PA6) was added to β-PP as rigid organic fillers and the parameterseffective on the crystallization behaviors were studied. The results indicated that the crystal formof PP was dependent on the nucleating capability of the second component. The crystallinity ofPA6with α nucleating capability directly affects the β nucleating capability of PP.