Surface modifiers titanate treated

Special surface modifications are available to further improve reinforcement. The objective of the surface treatment is to increase filler loading and/or improve physical properties without loss of rheological characteristics. A variety of surface-modified kaolins have been introduced including clays treated with silane, titanate, polyester, and metal hydroxide. Silane-treated kaolin is used in applications requiring maximum aging characteristics in the service environment. 

Surface modifiers can be added to the talc by the talc supplier to improve or reduce various talc-polymer interactions. The choice and concentration of the modifier depends on the desired benefit in the talc composite. Silanes and titanates are used to improve the bond between the talc surface and the polymer. Other surface modifiers, such a glycols and sorbates, are used to improve dispersion of the talc in the polymer. Stearates, such as zinc or calcium stearate, are added to the talc or mixed into the compound to reduce die drool and lubricate die surfaces. Epoxies can be used to minimize interactions between talc and certain stabilizers or metal impurities. These surface-modified talc products are generally more expensive than untreated talc. The decision to use a surface-treated talc is based on cost-performance balance. Sometimes it is more cost-effective to add any additives during the compounding operation than have them added to the talc by the talc supplier. 

Kaolin deposits are cored and analyzed before mining to determine quality. Mined clays are then either wet or dry processed by air floatation or water fractionation. Surface-modified clays can be made by treating standard, delaminated, and calcinated grades with surface modifiers. The treatment can be performed by either the supplier or the end user. These surface modifiers include silane, titanate, polyester, and metal hydroxide. The objective of these surface treatments is to increase filler loadings and/or improve physical properties such as melt viscosity, thermal stability, and modulus without loss of physical characteristics. Electrical applications represent the largest use of surface-modified kaolin in plastics. 

Figur 7.10 Variation of primary normal stress difference with shear stress for calcium carbonate filled polypropylene treated with titanate surface modifier ITS. Open symbols represent Weissenberg rheogoniometer data and closed symbols represents Han slit/capillary rheometer data. (Reprinted from Ref. 34 with kind permission from Society of Plastics Engineers Inc., Connecticut, USA.)...

The surface morphology of whiskers can be characterized and analyzed by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). Elgures 3.19 and 3.20 show SEM images and EDS spectrum of potassium titanate whiskers treated with polymethyl methacrylate (PMMA). According to the SEM results, the surface of unmodified whiskers is smooth without attachments, while the surface of modified whiskers is rough with attachments. The EDS spectrum of modified whiskers shows the characteristic peak of carbon (C). Both SEM and EDS results prove that the whisker surface is cladded with PMMA molecules.35... 

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