Polyurethane Reinforcing fillers

This technology was first commercially applied to polyurethane blend [121] and patented as Rimplast (for Reactive Injection Molding), but many polymers have since been blended with polysiloxane thanks to this method polyethylene [122], polypropylene [122,123], polyamide [124-130], polyesters [128,131-133], poly(phenylene ether) [134], fluorocarbons [135] and many more. Many of them include reinforcing fillers such as fumed silica. The silicone base involved can moreover contain reactive groups such as the epoxy group [136,137]. A typical silicone base useful for these blends was de-... 

Reinforced RIM (RRIM) elastomers are used. By the addition of reinforcing fillers such as milled glass fiber, glass flake, or mineral fillers in the polyurethane or short to long glass fiber in preforms, fabric, or mat forms placed in the mold cavity, the properties of the material can be altered to meet high performance requirements of the part (Chapter 15). The reinforced elastomers are used to increase flexural modulus, improve thermal properties, and improve dimensional stability.267... 

Research on the pyrolysis of thermoset plastics is less common than thermoplastic pyrolysis research. Thermosets are most often used in composite materials which contain many different components, mainly fibre reinforcement, fillers and the thermoset or polymer, which is the matrix or continuous phase. There has been interest in the application of the technology of pyrolysis to recycle composite plastics [25, 26]. Product yields of gas, oil/wax and char are complicated and misleading because of the wide variety of formulations used in the production of the composite. For example, a high amount of filler and fibre reinforcement results in a high solid residue and inevitably a reduced gas and oiFwax yield. Similarly, in many cases, the polymeric resin is a mixture of different thermosets and thermoplastics and for real-world samples, the formulation is proprietary information. Table 11.4 shows the product yield for the pyrolysis of polyurethane, polyester, polyamide and polycarbonate in a fluidized-bed pyrolysis reactor [9]. 

Ferrarinl, J. Cohen, S. "Reinforcing Fillers In Polyurethane RIM Proc. Annual Conference of the Reinforced Plastics/ Composites Institute, 1982, p. 37. 

The highly filled polyurethane joints that were studied are described in Fig. 24.8 [20]. The polymer chains on both sides of the interface are hydroxytelechelic poly butadiene chains (HTPBs). On the one hand, we have PUg in which the main additives are diisocyanate (isophorone diisocyanate) and 80% of reinforcing fillers (aluminum and potassium chloride). On the other hand, PUa contains the same diisocyanate and only 20% of reinforcing filler (carbon black). 

In urethanes the presence of these strong physical-chemical bonds helps to explain some of the properties of solid polyurethane elastomers. High modulus in tension and compression can be achieved without extending the elastomeric macromolecular structure with reinforcing filler. This means that elastic materials can be obtained with a level of hardness not possible with conventional rubbers. 

MMT is a reinforcing filler in polymers such as poly(urea urethane) (Ge et al. 2000) as evidenced by the very significant increase in mechanical properties of the composite nanofibers. Unfilled polymer nanofiber mats of polyurethane (PU) (M — 150,000 g/mol) were electrospun from llwt% solution in DMAc/THF (7 3wt/wt) into nanofibers with 150nm to 410nm. The tensile properties of these mats are shown in Table 6.4, where the last digit in the nanofiber designation is the weight fraction of MMT in the polymer. Based on the WAXD patterns for the composite nanofibers, MMT appeared to be well dispersed, exfoliated, and oriented in the axial direction of the samples. 

One of the first reports on polyurethanes reinforced with nanocellulose crystals was the paper published by Marcovich and co-workers [22]. In this report, nanocrystals were obtained from synthetic microcrystalline cellulose by acid hydrolysis and re-dispersion into dimethyl formamide (DMF) by ultrasonication to obtain a stable suspension. The suspension was an effective means for incorporating the cellulose crystals into the unreacted polyol-isocyanate mixture, utilized to produce polyurethane composite films. The rheology of the uncured liquid suspensions revealed the formation of a filler... 

Y. Li, A. J. Ragauskas. Cellulose nano whiskers as a reinforcing filler in polyurethanes,... 

Treated rubber is the only known reinforcing, elastomeric filler. The use of surface-modified rubber, in general, does not make the formulation harder and less flexible. In contrast, most other fillers are inorganic minerals, which reduce the elastomeric properties of a polyurethane formulation. Oils are used as fillers for some polyurethanes and to increase their flexibility. However, oils are certainly not reinforcing fillers, and they significantly reduce overall properties. 

In 1966, a new class of polyols that were highly useful in enhancing the modulus of polyurethane foams and elastomers, while maintaining other desirable properties, was introduced to the marketplace (66, 67). These polyols had the unique feature of containing in situ, free-radical polymerized vinyl polymer particles that were grafted to the polyol. The final product, which was termed a polymer polypi, is a conventional or an ethylene oxide-capped poly(propylene oxide) polyol that contains a stable dispersion of the vinyl polymer that acts as a reinforcing filler. When monomers such as acrylonitrile and styrene/acry-... 

Different core materials are used. They include foam, honeycomb core (plastic, paper, aluminum, etc.), ribs, balsa wood, filler spacers, corrugated sheet spacers, etc. Materials such as polyurethane foam, cellulosic foams, and polystyrene foams are widely used as core materials. Plastics, such as glass-reinforced polyester, are frequently used as the skins for panels. Different skin materials are used such as metallic skins alone or in conjunction with plastic skins. 

Figure 9. Reinforcing and nonreinforcing filler (volume fraction = 0.5) in poly(l,2-oxypropylene)-type polyurethane rubber. I = 0.74 min. 1 T =...

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