Gel coats properties

Unsaturated resias based on 1,4-cyclohexanedimethanol are useful ia gel coats and ia laminating and molding resias where advantage is taken of the properties of very low water absorption and resistance to boiling water (6). Thermal stabiHty is imparted to molding resias, both thermoplastic (71,72) and thermoset (73—76), enabling retention of physical and electrical properties at elevated temperatures (77). Additionally, resistance to chemical and environmental exposure is characteristic of products made from these resias (78). 

To overcome the poor mechanical properties of polymer and gel polymer type electrolytes, microporous membranes impregnated with gel polymer electrolytes, such as PVdF. PVdF—HFP. and other gelling agents, have been developed as an electrolyte material for lithium batteries.Gel coated and/ or gel-filled separators have some characteristics that may be harder to achieve in the separator-free gel electrolytes. For example, they can offer much better protection against internal shorts when compared to gel electrolytes and can therefore help in reducing the overall thickness of the electrolyte layer. In addition the ability of some separators to shutdown... 

A common and well-known method to prepare silica membranes with molecular sieving properties is sol-gel coating [3-5], With this technique, microporous silica layers with a pore-size of about 0.5 nm are dip-coated on top of supported y-alumina membranes. The supports are porous a-alumina disks with pore diameters in the range from 100-200 nm. On top of these macroporous supports a 3 pm thick mesoporous y-alumina layer is coated, with a pore size of 3 nm. 

Giovanardi, R., and Veronesi, P. (2014a) Corrosion behavior and mechanical properties of bioactive sol-gel coatings on titanium implants. Mater. Sci. Eng. C. doi 10.1016/j.msec.2014.07.044... 

Chen and Birley [16,17] demonstrated that the residual stress state can contribute to absorption of water providing a thermodynamic mechanism akin to osmosis. Blisters were shown to occur at the interface between the gel-coat and structural resins, and they were attributed to localised residual stresses. To avoid blister formation on immersion in water or other aqueous environments, the presence of impurities, which can act as osmotic centres, needs to be minimised, and the properties of any gel-coat or surface finish should be matched to those of the structural resins. 

In common with most plastics, polyester resins have good all-roimd resistance to chemical attack and corrosion, but all significant conditions must be known before a particular resin is specified. Improved corrosion-resistance is usually based on iso- or terephthalic acid and neopentyl glycol, giving good mechanical properties. These resins are also suitable for gel coats that are continuously stressed with warm water (such as... 

---