Precipitated silica

About: Precipitated silica is a research topic. Over the lifetime, 1401 publications have been published within this topic receiving 20992 citations.

Lead acid battery separator with improved electrical and mechanical properties

Abstract: An oxidation resistant, microporous polyolefin web exhibiting high-strength mechanical and low electrical resistance properties is a solid matrix that includes an ultrahigh molecular weight polyolefin component and a friable precipitated silica component. The ultrahigh molecular weight polyolefin component provides high-strength mechanical properties to the web. The friable precipitated silica component is broken down into predominately discrete silica aggregates dispersed throughout the microporous web to maintain a low electrical resistance in the presence of an electrolyte. In an alternative embodiment, a polyethylene web includes an antioxidant coating that is applied to the separator web following extraction of the majority of the process oils and drying of the extraction fluid from the separator pores. The resultant 'sheath' of antioxidant protects the mechanical integrity of the polyethylene separator by suppressing polyethylene degradation.

Rubber composition comprised of functionalized elastomer and starch composite with coupling agent and tire having at least one component thereof

Abstract: The present invention relates to a rubber composition comprised of a functionalized elastomer which contains a dispersion of a starch/plasticizer composite and coupling agent and to pneumatic tires having at least one component comprised of such rubber composition. The rubber composition may also contain one or more additional elastomers and may contain at least one particulate reinforcing agent selected from, for example, precipitated silica aggregates, carbon black and carbon black which contains silica domains on its surface. Such tire component can be, for example, its circumferential tread or other component of the tire.

Effect of compatibilizer on the dispersion of untreated silica in a polypropylene matrix

Abstract: BACKGROUND: A new processing method for polypropylene-untreated precipitated silica (PP/SiO2) Composites based on the incorporation of a second polymer phase of polyamide 6 (PA6) is presented and compared with a more classic one making use of compatibilizers: glycerol monostearate (GMS), ethylene acrylic acid ionomer (IAAZE) and maleic anhydride grafted polypropylene (NIA-graft-PP). The effects of processing methods and conditions on the microstructure and properties Of PP/SiO2 Composites prepared by melt compounding are investigated with a view to reduce the size of aggregates of silica from the micrometre to the nanometre scale and to improve the link between filler and matrix. RESULTS: On the one hand, the presence of GMS and LAAZE compatibilizers significantly improves the dispersion of the silica particles. On the other hand, when using a PA6 second phase, the SiO2 particles are dispersed in PA6 nodules. Within these nodules, SiO2 appears dispersed at the nanoscale but with larger particles ('aggregates') of about 200 nm. Significant improvements in tensile strength and modulus are obtained using MA-graft-PP compatibilizer. An increase in impact strength is observed in the case of GMS compatibilizer. Thermal parameters indicate also that silica plays the role of nucleation agent for PP matrix. All improvements (tensile strength, modulus and impact strength) increase with the addition of compatibilized PA6 second phase. CONCLUSION: By the incorporation of masterbatch of silica in PA6 as a second polymer polar phase, a successful new production method for PP/SiO2 nanocomposites has been developed. Interestingly, this method does not require any (expensive) pre-treatment of the silica. (c) 2007 Society of Chemical Industry.

In-situ precipitation of reinforcing titania fillers

Abstract: The technique developed for precipitating reinforcing silica into an elastomer is extended to titania fillers by hydrolyzing a titanate instead of a silicate. Of the three catalysts studied, namely HCl, NH4OH, and (C2H5)2NH, the NH4OH was the most efficient, introducing as much as 65 wt % titania into a poly(dimethylsiloxane) network in twelve hours. Stress-strain measurements in elongation showed the nature and extent of the reinforcement to be very similar to that obtained from insitu precipitated silica.