Polyurethane Polyurethanes, hybrid

Polyurethane sealant formulations use TDI or MDI prepolymers made from polyether polyols. The sealants contain 30—50% of the prepolymer the remainder consists of pigments, fiUers, plastici2ers, adhesion promoters, and other additives. The curing of the sealant is conducted with atmospheric moisture. One-component windshield sealants utili2e diethyl malonate-blocked MDI prepolymers (46). Several polyurethane hybrid systems, containing epoxies, siUcones, or polysulfide, are also used. 

Property Epoxy Polyurethane Polyester Hybrid AcryHc... 

For some years there has been concern at the amount of styrene vapour in workshops preparing reinforced polyester laminates. More recently this has increased interest in polyester-polyurethane hybrids and in the further development of closed moulding and resin transfer moulding techniques as well as greater use of lower styrene levels. 

Belva, F., Bourbigot, S., Duquesne, S., Jama, C., Le Bras, M., Pelegris, C., and Rivenet, M., Heat and fire resistance of polyurethane-polydimethylsiloxane hybrid material, Polym. Adv. Technol. 2006, 17, 304. 

Low modulus elastomers are materials that have found wide use in the automobile industry for fascia, bumper covers, and trim parts. Other applications include integral window seals and a wide variety of applications where it is replacing molded rubber. Most of these materials are not pure polyurethane, but polyurethane/polyurea hybrids with improved processing and properties when compared with the earlier allurethane systems. 

Kusakabe K, Seiki Y, and Morooka S. Separation of benzene/cyclohexane mixtures using polyurethane-silica hybrid membranes. J Membr Sci 1998 149 29-37. 

Matrix Plastic Foams. The matrix for plastic foams includes rigid polyurethane foam, urethane-modified isocyanurate foam, unsaturated polyester-polyurethane hybrid foam, and vinyl ester-polyurethane hybrid foam. 

Hydroxyl-Containing Unsaturated Compounds/Polyurethane Hybrid Foams. Unsaturated polyesters have terminal hydroxyl groups and unsaturated linkages in the polymer skeleton (34). Vinyl esters have terminal vinyl groups and pendant hydroxyl groups. These model structures are shown in Equations (1) and (2) respectively. 

Methacrylate-modified unsaturated polyester/polyurethane hybrid resins (as matrix resins, not foamed products) were developed by Ashland Chemical (33, 40). 

Hybri-Chem. [Hybti-Chem] Polyesto/ polyurethane hybrid system for open mold casting, lamination, spray appUc., resin transfer molding, tooling. 

S. Chen, J. Sui, L. Chen, and J. A. PotMAN, Polyurethane-nanosilica hybrid nanocomposites synthesized by frontal polymerization, J. Polym. Sci. Part A - Polym. Chem., 43 (2005), pp. 1670-1680. 

A New Tendency in the Environmental Industry Polyurethane Hybrid Membranes... 

Saucedo-Rivalcoba, V., Martinez-Hernandez, A. L., Martinez-Barrera, G., Velasco-Santos, C., Rivera-Armenta, J. L. Castano, V. M. (2011b). Removal of hexavalent chromium from water by polyurethane-keratin hybrid membranes. Water. Air. Soil Pollut. 218, 557-571. 

Chem. Descrip. Aliphatic polyurethane/acrylic hybrid disp. with n-methyl pyrrolidone cosolv. 

Kukanja, D., Golob, J., Zupancic-Valant, A., and Krajnc, M. 2000. The structure and properties of acrylic-polyurethane hybrid emulsions and comparison with physical blends. Journal of Applied Polymer Science 78(l) 67-80. 

Xtcon Polyester/polyurethane hybrid resin Amoco Chem. Co. 

Y. Wei, C. Zong, F. Wang, Preparation of vinyl polymer/polyurethane hybrid latex particles and their application in nano-sized vinyl polymer particle/thermoplastic polyurethane blends, E-Polymers 10 (1) (2010). 

Cho JW, Lee SH (2004) Influence of silica on shape memory effect and mechanical properties of polyurethane-silica hybrids. Eur Polym J 40 1343-1348... 

Hyrizon, Polyester-polyurethane hybrid foam system, Aristech Acrylics LLC... 

The preparation of aqueous acryUc-polyurethane hybrid emulsions by semi-batch pulsion polymerisation of a... 

Yim T-J, Kim SY, Yoo K-P (2002) Fabrication and thermophysical characterization of nanoporous silica-polyurethane hybrid aerogel by sol-gel processing and supercritical solvent drying. Korean J. Chem. Eng. 19(1) 159-166. 

Jeon HT, Jang MK, Kim BK, Kim KH (2007) Synthesis and characterization of waterborne polyurethane-silica hybrids using sol-gel process. Colloids and Surface A Physicochem. Eng. Aspects 302 559-567. 

Apart from the development of polyurethane adhesives and sealants with isocyanate reactive groups, a new type of silane-terminated polymer adhesive has been developed called Polyurethane (PUR)-Hybrids. They and modified silicones (MS) and provide the benefits of ... 

Poiyeste r/polyurethane hybrid Pol rethane/polyurea h rid RIM application... 

Most work has been with free-radical systems but other chemistries can be used. Begishev etal. studied frontal anionic polymerization of e-caprolactam [18, 19], and epoxy chemistry has been used as well [20-23]. Mariani ctal. demonstrated frontal ring-opening metathesis polymerization [17]. Fiori et al. produced polyacrylate-poly(dicydopentadiene) networks frontally [24], and Pojman etal. studied epoxy-acrylate binary systems [25]. Polyurethanes have been prepared frontally [13,14, 26]. Frontal atom transfer radical polymerization has been achieved [16] as well as FP with thiol-ene systems [27]. Recent work has been done using FP to prepare microporous polymers [28-30], polyurethane-nanosilica hybrid nanocomposites [31], and segmented polyurethanes [32]. 

Figure 6-9. A Xycon TS polyester-polyurethane hybrid resin from Amoco Chemical Co. was used for the body panels in this futuristic GM XT2 EL Camino. When compared to unsaturated TS polyesters, this Xycon resin with Amoco s Thomel carbon filter offers greater inherent strength, is less brittle, and requires a lower curing temperature and no postcuring.

Thus, in alkyd-acrylic systems, the final product contains free acrylic polymer, grafted acrylic-alkyd polymer, and free alkyd resin [95]. Polyurethane-acrylic hybrids present a polymer network formed by acrylic chains linked by both polyurethane chains and pure acrylic connections [76]. 

Lopez A, Degrandi E, Cretan C, Canetta E, Keddie JL, Asua JM. Waterborne polyurethane-acrylic hybrid nanoparticles by miniemulsion polymerization applications in pressure-sensitive adhesives. Langmuir 2011 27 3878-3888. 

Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM) followed by dynamic mechanical parameter tests were used for the investigation of the morphology of unsaturated polyester/diol-polyurethane hybrid polymer networks (UP/PU HPNs). The effect of phase separation on mechanical properties was described [142]. 

The adhesives can have open times varying from a few seconds up to about 10 minutes to match application requirements. Improvements related to adhesives that have long open times and/or high green strength via the use of urethane diols or polyurethane-acrylic hybrid systems has been reported [42]. 

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