Hydrophilic fillers

Hydrophilic Fillers (Si02, Ti02, Zr02) and Ormosil Networks.801... 

Hydrophilic Fillers (SiOj, Ti02, ZrOj) and ORMOSIL Networks.596... 

Prepared filaments and fibres are applied not only in the floor coverings as the most important utilization for PP, but also medical, hygienic, apparel, automotive and/or agricultural sectors became crucial, for applications such as disposable diapers, sports underwear and equipment, artificial grass, geo textiles, ropes, car seats, oil wipes, wet and dry filters or membranes. Physical and chemical properties of polyolefins fibres are developed for many applications, in order to increase comfort characteristics, tensile strength, and/or other utility properties they are often blended, co-processed or combined with other materials such as polar acrylics, wool, bonding agents, hydrophilic fillers, or stabilizers. 

Hydrophilic filler Hydrophobic plus (meth)acrylic acid Core hydrophobic Shell plus acrylic acid Water retention in plastics... 

The low porosity of compressed tablet may require use of hydrophilic fillers to improve the dissolution rate that may be at the expense of drug/polymer interactions. 

The problems associated with starch extrusion are increased when starch nanocomposites are processed using hydrophilic fillers. As it was explained before, although these fillers are compatible with starch and glycerol, they tend to clump together obstructing their dispersion in the matrix. 

Fire resistant water containing epoxy composites have been developed and studied in the chapter. The influence of hydrophilic filler content on the fire resistance of epojgr polymers based on epoxy oUgomers has been estabhshed. 

In the research the influence of hydrophilic filler content on the fine resistance of composites based on epoxy resin ED-20 was investigated. 

FIGURE 19.1 Dependence oftemperature on the nonheated sample side on flame exposure time 1 initial epoxy component 2-epoxy composite containing hydrophilic filler. 

As it is seen in Fig. 19.1, the test sample damage takes place on the 15th sec, which is evidenced by temperature fluctuations on curve 1. The filled sample (contains 15% of the hydrophilic filler) maintains the integrity up to 50 sec the sparking is observed at combustion that is, probably, related to water injection into the combustion zone. Besides, when the flame source is eliminated, the sample self-extinguishes for 2-3 sec. 

The efifect of hydrophilic filler content (5-20%) on the fire resistance of the composites was also studied in the chapter (Fig. 2). 

When measuring temperature on the nonheated surface of water containing composites within a specified time span, it was established that the fire resistant properties improve with increasing hydrophilic filler content from 10% to 20% the sample with filler content of 5% was damaged by 33 sec. 

The data obtained in combustibihty tests of water containing compositions are illustrated in Fig. 19.3. The best results were obtained with filler content of 15 and 20%. In this way, the flame spread rate for the initial sample is 18 mm/min and, when the hydrophilic filler is used, it is equal to 3 mm/min. 

Petinakis, E., Liu, X., Yu, L., Way, C., Sangwan, P., Dean, K., et al., 2010. Biodegradation and thermal decomposition of poly (lactic acid)-based materials reinforced by hydrophilic fillers. Polym. Degrad. Stabil. 95, 1704-1707. 

While unique properties, such as dimensional stability or increased hardness and modulus, are the usual motivation for exploiting particulate filled composites, special attention must be paid to other mechanical properties, such as yield and ultimate strength and fracture toughness [1 ]. Due to the low adhesion between non-polar hydrophobic polymer matrix and hydrophilic filler surface, the interfacial debonding is very frequently the first step of failure in these materials [2]. Mainly for this reason the effective application of particulate composites is first of all determined by the interfacial interaction between polymer and filler. 

Most fillers - calcium carbonate, kaolin, mica and wollastonite - have polar surfaces. Conversely, many polymers, such as the polyolefins, are hydrophobic. These will not readily wet hydrophilic fillers. It is therefore necessary to treat the filler surface to facilitate intimate polymer-mineral contact. Surface treatments also act as internal lubricants and improve the dispersion of the filler in the plastic matrix and the flow characteristics of the filled polymer. A further effect of some surface treatments is to improve the mechanical properties when exposed to water in vapor or liquid form, especially at high temperatures. These topics are discussed in detail in the chapter Mi era/ Surface Modification. 

Thermal-type electric breakdown is generally attributed to dielectric losses introduced primarily by ionic conductivity. In some cases, water absorbed by the plastic dissolves ionic impurities in the material. Moisture may also be absorbed on the surface of hydrophilic filler or fibers (eg, glass fiber), thereby introducing dielectric losses. Chemical attachment to the polymer molecule also increases dielectric losses. 

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