Thermoplastic particle

The iQ automotive battery incorporates a micro-chip which monitors and controls the electrochemical process of the lead-acid battery, as well as its physical environmental and operating conditions. The thermal insulation of the battery also plays an important role. Neopolen P, a thermoplastic particle foam from BASF which can be processed completely without blowing agents, was chosen for this application. The foamed battery container calls for a solid frame that can be mounted onto the car body, and this frame is configured as a solid PP injection-moulded article, and fused to the container. 

The most frequently applied methods for improving toughness are the addition of preformed particles or the in-situ formation of dispersed rubbery or thermoplastic particles in the thermoset matrix (Chapter 8). 

Due to the difference of expansion coefficients between the particles and the matrix, different kinds of stress fields may be developed (Raghava, 1987). Rubbery and thermoplastic particles are placed in a hydrostatic tension... 

In the case of thermoplastic particles, because the bulk modulus is equivalent to that of the matrix, no cavitation is observed. 

In the case of thermosets toughened with thermoplastics particles (Sec. 13.4), this mechanism may be of a considerable importance because of the intrinsic toughness and/or ductility of these particles. 

An improvement in the toughness of thermosets can be favored by rubber or thermoplastic particles, which operate both in crack initiation and propagation mechanisms. The different toughening mechanisms can act simultaneously and can be modeled quantitatively. 

Thermoplastic-modified siloxanes are produced by polymerization of monomers such as styrene, methyl methacrylate or vinyl acetate in the presence of e.g. ot,(i)-dihydroxy-poly(dimethylsiloxane). The reaction can be so controlled that the thermoplastic particles are formed as rods. These, depending upon their type and quantity, determine the mechanical properties of I he vulcanized. silicone resin obtained via cro.sslinking of the silicone component. Such products are utilized in the porcelain, electric, electronic and metal industries. 

Figure 6.5 Self-healing by embedded thermoplastic particles in a thermosetting polymer matrix. Source [31] Reproduced with permission fiom SAGE...

I SMP based foam Thermoplastic particle SMP molecule Thermoplastic molecule... 

Tg - Glass transition temperature of SMP fiber Tm - melting temperature of thermoplastic particles Tgp - glass transition temperature of the thermoset polymer matrix and Tc - curing temperature of the thermoset polymer matrix. Requirement Tgp>Tm>Tg>Tc-... 

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