Curing of polymers

Clock-type induction periods occur in the spontaneous ignition of hydrocarbon-oxygen mixtures [2], in the setting of concrete and the curing of polymers [3]. A related phenomenon is the induction period exhibited... 

Similar types of cross-linking reactions are observed for polymers to which photosensitive molecules ate chemically attached to the backbone of the polymer stmcture (Fig. 7). Radiation curing of polymers using uv and visible light energies is used widely in photoimaging and photoresist technology (Table 8) (58,59). 

D. R. RandeU, ed.. Radiation Curing of Polymers, Royal Society of Chemistry, Burlington House, London, 1987. 

Curing primarily refers to the process of solidification of polymer matrix materials. Metal matrix materials are simply heated and cooled around fibers to solidify. Ceramic matrix and carbon matrix materials are either vapor deposited, mixed with fibers in a slurry and hardened, or, in the case of carbon, subjected to repeated liquid infiltration followed by carbonization. Thus, we concentrate here on curing of polymers. 

Uses. Curing of polymers cross-linking of textile fibers prevention of microbial spoilage... 

Another practical example of using Raman in a process environment is to monitor the curing of polymers. Raman spectra as a function of time for the... 

There are many other practical examples of using chemometric methods to make Raman spectroscopy into a real-time monitoring method (14-18). One such example is the use of Raman for process control in the curing of polymers (18). The Raman spectra of a commercial cyanate ester resin,... 

Gas-phase curing of polymer fibers with trichlorosilane followed by pyrolysis gave high-nitrogen, low-carbon, silicon-nitride-type fibers. 

Lattice models consist of spanning the system of interest by meshes or nodes. Molecules that are moving or reacting are lumped into coarser particles, and the nodes or the meshes keep a track of the extent of mobility or reaction. Examples include curing of polymers, diffusion in porous structures, and stress calculations in materials. 

A more recent development is temperature-modulated DSC (Jones etal, 1997), which is a particular example of the broader area of modulated calorimetry (Gmelin, 1997) and enables deconvolution of kinetic and thermodynamic processes during the reactive curing of polymer networks (Van Assche et al, 1997). This is discussed in more detail later (Section 3.2.3). 

One of the most efficient methods for rapid generation of highly crosslinked polymers is by exposing multifunctional monomers to UV radiation in the presence of a photoinitiator. A liquid resin can be transformed within a fraction of a second into a solid polymer that is very resistant to chemical, heat and mechanical treatments. A review of UV curing of polymers is presented by Decker (1989). ... 

Thermogravimetric analysis was used to follow the curing of polymer films. This technique is predicated on the volatility of the unreacted components. In the present study the volatile components have been determined to be EEA, HDODA, TMPTA, Irgacure 651, and their volatile reaction products. The Epocryl 370 resin and the VTBN rubber were found not to contribute to the volatiles. Decomposition of the mixtures generally took place about 310-350°C in all cases, including the rubber modified samples. 

The future activities of the Institute for the Organic Synthesis and Photoreactivity, together with the Department of Chemical Engineering, Processing and Materials of the University of Palermo, will be focused in the better characterization of the influences of the processing parameters and additives in the radiation curing of polymers. 

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