Present microelectronic photoimaging applications employ onium salts for deep UV (I-line, 365 nm) photolithography. Since most onium salts do not absorb at this wavelength, photosensitizers are commonly employed. Polynuclear aromatic hydrocarbons are the most efficient known examples of electron-transfer photosensitizers for onium salts. However, they have serious drawbacks that limit their use, such as they are expensive, toxis, and poorly soluable in most reactive monomers and polymer systems.
A living polymerization process is one that can produce polymers of predetermind molecular weight and a narrow molecular weight distribution containing one or more monomer sequences, the length and composition of which are controlled by stoichiometry of the polymerization reaction and degree of conversion. One such process is reversible addition-fragmentation-termination (RAFT). While compounds made by RAFT function effectively as chain transfer agents, they share one major disadvantage with the entire class of sulfur-based compounds: a characteristic disagreeable odor.
As part of the continuing effort to reduce the environmental impact of various industrial chemical processes, there has been a strong emphasis in developing new methodology for the application and cure of organic coatings. While these ubiquitous materials are absolutely essential to modern life, they also constitute one of the primary industrial Sources of emissions of Volatile organic Solvents that contribute to air and water pollution.
Anionic polymerization processes variously termed living, controlled, or immortal are used to synthesize polymers having a narrow molecular weight distribution and low polydispersity (1.5). These processes are so named because polymerization generally occurs by addition of monomer units to a constant number of growing polymer chains until all monomer has been consumed; if more monomer is added, polymerization resumes.
This technology relates to a photopolymerizable class of vinyl ether oligomers which can find application in the areas of coatings, adhesives, printing inks, photoresists and high impact composites. The versatile photopolymerization capability makes these oligomers an excellent strategic candidate for shrinkage control coatings in place of acrylates. These oligomers include photopolymerizable functional groups which manifests excellent uniform film forming characteristics when cured by UV or electron beam radiation.
Oxide glasses with earth ions have a number of different applications including: lasers, optical switches, optical amplifiers and have anti-glare properties. These rare earth glasses, however, come with a number of problems including concentration quenching, low solubility, and inhomogenous distributions of the glass components. This invention tackles these issues by providing a process for preparing rare earth containing glasses. The glass is treated at a higher temeprature than the spinodal temperature, causing it to be homogeneous, clear, and reduced concentration quenching.
In photoinitiated cationic ring-opening polymerization, the polymerizable substrate is subjected to irradiation with light for a brief period during which the photopolymerization must proceed essentially to completion. Consequently, only monomers that undergo very high rates of polymerization may be employed. Certain epoxide monomers display high reactivity in photoinitiated cationic polymerization and are suitable for such uses while most other undergo sluggish reaction and are not usable.
There are two basic classes of adhesives in widespread current use. The first class is pressure sensitive adhesives, such as are employed in adhesive tapes. The second class is reactive adhesives, used primarily for structural purposes. A long-standing problem with these types of adhesives is that they are unable of obtaining both a long working life and a rapid cure time.
This invention is directed to a new, inexpensive analytical instrument that can be used to study and evaluate such essential parameters as light intensity, photoinitiator concentration, and monomer reactivity in a wide variety of UV photopolymerization curing applications. The device provides real-time information as the sample proceeds through the photoreactive phase. Through the direct, continuous, and remote monitoring of the sample using optical pyrometery, the temperature of the monomer undergoing photopolymerization can be obtained as a function of time.
Several methods for the preparation of polymeric microbeads for chromatographic separations in the pharmaceutical industry have been developed over the past several decades. However, those methods often result in microbeads with a wide distribution of sizes. This invention results in more uniform particle size but also microbeads that are derived from multifunctional epoxy monomers and that have residual epoxy functionality on their surfaces.