Liuqin Ge

Mechanical and thermal properties of polypropylene (PP) composites filled with CaCO3 and shell waste derived bio-fillers

The clam shell (CS) waste was first modified by furfural and hydrochloric acid to prepare fillers FCS and ACS, which were then used as fillers in polypropylene (PP), as well as the commercial calcium carbonate (CC). These fillers were characterized and analyzed by means of X-ray diffraction (XRD), atomic force microscopy (AFM), particle size analyzer, Fourier transformed infrared spectroscopy (FTIR) and contact angle measurement. The mechanical and thermal properties of PP composites were investigated as well. XRD analysis indicated that the major crystalline phase of CC was calcite; of shell waste derived fillers, calcite and aragonite. The CC was fully hydrophobic, while the shell derived fillers were amphiphilic. Mechanical property studies showed that the incorporation of FCS played the role mainly of toughening the PP; of CC, CS and ACS, that of reinforcing. The optimum filler contents of CS, ACS and FCS could reach 5, 7 and 15 wt.%, respectively, to obtain a good balance between fracture toughness and stiffness of the PP composites. Polarized optical microscopy (POM) observation indicated that the inclusion of these fillers could promote the heterogeneous nucleation of PP.

A potential bio-filler: The substitution effect of furfural modified clam shell for carbonate calcium in polypropylene

Shell waste has the potential to be used as a bio-filler. In this work, the commercial calcium carbonate and furfural modified clam shell were used as fillers in polypropylene. Both fillers were characterized and analyzed by X-ray diffraction, scanning electron microscopy equipped with an energy dispersive spectrometer, particle size analyzer, Fourier transformed infrared spectroscopy, and contact angle measurement. The mechanical and thermal properties of unfilled polypropylene and polypropylene composites were investigated as well. X-ray diffraction and energy dispersive spectrometer analysis indicated that the major phase of calcium carbonate was calcite; of modified clam shell, calcite and aragonite. The calcium carbonate displayed a cubic-like morphology with a smaller particle size as compared with that of modified clam shell. The contact angle measurements indicated that calcium carbonate was fully hydrophobic, while modified clam shell was amphiphilic. Thermal gravimetric analyses confirmed the reinforcement effects of both calcium carbonate and modified clam shell in polypropylene composites. Mechanical property studies showed that the inclusion of modified clam shell played the role mainly of toughening the polypropylene; of calcium carbonate, that of reinforcing, with a nonsignificant toughening effect. The optimal filler ratio of modified clam shell could reach 15 wt.%, as compared with 10 wt.% for calcium carbonate, making it possible for substituting calcium carbonate in polypropylene.

Finite Dilution Inverse Gas Chromatography as a Versatile Tool To Determine the Surface Properties of Biofillers for Plastic Composite Applications.

An improved understanding of a filler’s surface properties is important for determining the most effective polymer reinforcement fillers. In this work, the surface characteristics of two biofillers, namely, clam shell modified by hydrochloric acid (AMF) and furfural (FMF), were investigated using inverse gas chromatography (IGC). The IGC results showed that the dispersive surface energy (γ(S)(D)) contributed the major part to the total surface energy for the biofillers. The values changed as a function of surface coverages, meaning that both samples were energetically fairly heterogeneous. The γ(S)(D) calculated with the Dorris–Gray method was larger than that calculated with the Schultz method, with a γ(S,Dorris–Gray)(D)/γ(S,Schultz)(D) ratio of 1.10. Compared to AMF, FMF possessed higher γ(S)(D) value; however, this difference was compensated by specific (acid–base) surface energy (γ(S)(AB)). Both samples predominantly interacted with ethanol and acetonitrile, implying an amphoteric nature of the material surfaces. Gutmann acid and base number profiles indicated that the surfaces of both samples were more basic in nature. The FMF showed a lower total work of cohesion (W(Coh)(total)) value compared to the AMF, which could lead to an increase in composite performance.

Colorating and mechanical performance of low-density polyethylene (LDPE)/dye-loaded shell powder (DPSP) composites

Filling and colorating are two important procedures in the polymer production. In this work, a bio-filler dye-loaded shell powder (DPSP) was prepared at first and then its filling and colorating effects on low density polyethylene (LDPE) polymer were investigated. SEM analysis showed the good dispersion of DPSP and strong interfacial adhesion. Mechanical property studies indicated that the incorporation of DPSP had an excellent filling effect at lower loading rate. Uniform color distribution in the specimens was also obtained at the premise of improving the mechanical performance of LDPE polymer. Vicat softening temperature tests indicated that the incorporation of DPSP could enhance the heat resistance of the composites. The optimal additive amount of DPSP was determined as 10 wt.% with a good balance between toughness and stiffness of LDPE composites.