Characterization and modification of fillers for paints and coatings

This paper highlights the possibility of inverse gas chromatography for the surface characterization of common fillers (CaCO₃, talc, SiO₂,) for paints and coatings. Divided solids are described, on the one hand, by the dispersive component of their surface energy and, on the other, by a specific parameter indicating their acid-base interaction potential. The role of the surface morphology at a molecular level is also examined. It is demonstrated that steric effects play an important role in the adsorption of probes on lamellar solids like talc. The consequences of surface treatments as well as examples of practical applications are also reported.     

Recovery of monomers and fillers from high-temperature-vulcanized silicone rubbers—combined effects of solvent, base and fillers

The depolymerization of high-temperature-vulcanized (HTV) silicone rubbers containing filler silica and alumina into cyclosiloxane monomers and spontaneous recovery of fillers were studied. First, HTV silicone rubber was treated with different types of solvents in the presence of KOH to find that a triad mixture of diethylamine, methanol and hexane was appropriate not only to dissolve the silicone rubber to a suspension but also to separate fillers completely by filtration. The filtrate was distilled to remove solvent first and then give pure cyclosiloxane monomers in 76–84% yields. Second, the rubbers were treated with other types of triad mixture of solvents and bases, e.g. tetramethylammonium hydroxide, hexane and diethylamine. After filtration, residue was again treated with the amine and hexane to recover clean fillers in 83–93% yields. Cyclosiloxane monomers were also obtained from the combined filtrates in 67–78% yields.     

酚酞聚芳醚酮（PEK－C）填充料的研究

本文筛选出几种特定的酸性金属氧化物填料，研究了其粒度及粒子形状对ＰＥＫ－Ｃ的复合化效果和填充后的ＰＥＫ－Ｃ体系的力学性能、加工性能和结构形态。结果表明，ＴｉＯ２、Ｃｒ２Ｏ３、Ａ１２Ｏ３及ＭｏＳ２等与ＰＥＫ－Ｃ具有良好的亲合性，对ＰＥＫ－Ｃ起到了明显地增量、补强作用。在保持ＰＥＫ－Ｃ树脂的基本物理性能前提下，可降低注射用ＰＥＫ－Ｃ专用料的价格。     

Three-body abrasive wear behaviour of particulate-filled glass–vinyl ester composites

The incorporation of silicon carbide (SiC) and graphite fillers on three-body abrasive wear behaviour of glass–vinyl ester (G–V) composites has been investigated. Dry sand/rubber wheel abrasion tests (RWAT) were carried out at 200 rpm test speed. The tests were carried out at 22 and 32 N loads by varying the abrading distance from 270 to 1080 m in steps of 270 m. The worn surfaces were examined using scanning electron microscopy (SEM). The wear volume and specific wear rate of G–V composite reduces significantly on the addition of SiC filler. Graphite filler, however, performed poorly resulting deterioration in wear performance of SiC-filled G–V composite. The SEM studies indicate the reasons for failure of composites and influencing parameters.     

Controlled telescopic reinforcement system of fabric-cement composites — Durability concerns

The study objective was to modify the microstructure of AR glass strand to induce a controlled mode of telescopic bonding during service life, by using sub-micron particles absorbed between the filaments of the strand. Two groups of fillers were used: (i) pozzolanic fillers (silica fume) with 50 nm and 200 nm particle sizes; and (ii) polymeric fillers (polystyrene-based polymers), with two glass transition temperatures (− 6 °C and 100 °C). Composites were prepared using fabric reinforcement and tested for tensile behavior. Composite properties could be controlled by addition of fillers into the glass bundle, and the magnitude and efficiency of the modification was highly dependent on the filler type, structure, and properties. The best performance was obtained with silica fume fillers having relatively large 200 nm particles.     

以工业回收PS为载体的ABS用填充母料研制

以工业回收聚苯乙烯(IR-PS)为载体树脂,加入适量助剂与无机填料制成了ABS用填充母料(SM)它与ABS树脂相容性好,且降低了ABS制品的成本。本文从原材料选择、填充母料的物理性能、填充后ABS塑料的加工性能、制品的光学性能及实际应用效果等方面对该种填充母料的研制做了介绍。     

ADHESION OF ELASTOMER LAYERS TO AN INTERPOSED LAYER OF FILLER PARTICLES

Adhesion of elastomers to filler particles was studied by interposing a single layer of particles between two layers of a crosslinked elastomer and peeling the sandwich apart. Carbon black particles increased the peel strength by up to 100% compared with autohesion of the elastomer layers. Silica particles also increased the adhesion, but by a smaller factor, and there were significant differences using different elastomers. Also, the strength of adhesion depended on the degree of crosslinking of the elastomer layers: at higher levels of crosslinking, both self-adhesion and adhesion to particles were reduced. Nevertheless, this simple experiment gives an indication of the relative strength of adhesion for different combinations of elastomer and reinforcing filler.     

Calcium phosphates grown on bacterial cellulose template

Bacterial cellulose membranes were employed as templates for calcium phosphates deposition by successive immersion in solutions of Ca(NO₃)₂·4H₂O and (NH₄)₂HPO₄, under ultrasonication. During the wet chemical reaction, mineral phases were loaded on bacterial cellulose fibrils, leading to precursor hybrid composites. These were subjected to a lyophilisation procedure in order to preserve the 3D porous aspect and afterwards to a thermal treatment with the aim of removing the polymeric phase and generating well crystallized structures. Different types of morphologies were achieved by varying the heating rate, as well as the calcination temperature and period. The as-prepared samples and the final ones were investigated from compositional and structural point of view through X-ray diffraction and Fourier-transform infrared spectroscopy and morphologically concerning by scanning electron microscopy. The magnetic properties were also evaluated in order to demonstrate the suitability of the obtained materials for the development of magnetic scaffolds dedicated to hard tissue applications.     

Sealing behaviour of glass-based composites for oxygen transport membranes

In this study, seven different filler materials in different proportions were added to a Ba-Ca-Si glass matrix “H” to investigate new sealant with higher thermal expansion coefficient (CTE) value and good sealing performance for application in oxygen transport membrane (OTM). SrTi_0.75Fe_0.25O_3-δ (STF25) was used as an OTM, and the sealing partners were ferritic steel Aluchrom and pre-oxidized Aluchrom. Compatibility tests were carried out to investigate the feasibility of the composites. Higher CTE values were found in dilatometer tests on composite samples by adding 40 wt% Ag (HAg40) and 30 wt% Ni-Cr (HNC30). Gas-tightness measurements of sandwiched samples produced appropriate helium leakage rates in the range of 10^?6 mbar·l·s^?1. Sealing behaviour of sealants HAg40 and HNC30 were investigated by joining STF25 and as-delivered/pre-oxidized Aluchrom together. Scanning electron microscopy (SEM) on cross-sections of the joints revealed a homogeneous microstructure and good adherence of the glass sealants to support metals and STF25.     

高填充,高性能PE薄膜专用填充母料的研制

文章介绍了高填充，高性以ＰＥ薄膜专用填充母料生产中填料的选择，母料中分散剂体系对ＰＥ薄膜性能的影响及该母料在ＰＥ垃圾袋中的应用。