Photocrosslinking moiety

Sulfonated PAES with photocrosslinkable moieties have been synthesized by the direct copolymerization... 

H., Synthesis of polymers having photocrosslinkable moieties for second-order nonlinear... 

Photocrosslinking. The second class of photopolymer chemistry that is used in some commercial products is based on the reaction of unsaturated moieties attached to an organic polymer. These photopolymer materials include the [2+2] cycloaddition of the ethylenic groups in poly(vinyl cinnamate) polymers and in the newer styryl pyridinium (10) and thiazolium (77) derivatives of poly(vinyl alcohol). The main advantage of this chemistry is that, unlike free-radical photopolymerization, they are insensitive to the presence of oxygen. This photopolymer mechanism is principally used in applications employing a washout development process (e.g. resists). 

Modifications of this approach have led to ABPP probes that are capable of selectively labeling the pi and p5 subunits of the proteasome [138]. In further studies of the proteasome, bifunctional ABPP probes containing a vinyl sulfone linked to a photoreactive moiety allows photocrosslinking of subunits adjacent to proteasomal catalytic sites [139]. 

Polymeric systems containing side-chain benzoin moieties, recently appearing [100,102] in the patent literature, have been applied as photoinitiators to UV curing of prepolymers of a different nature. In particular, siloxane-compatible photocrosslinking initiators (PSBME) are manufactured [100] by reacting silox-anes with benzoin ether derivatives (Scheme 23) and used in UV curing of acryloxypropyl-terminated dimethylsiloxane prepolymers. 

Nakayama Y, Matsuda T (1992) Preparation and characteristics of photocrosslinkable hydrophilic polymer having clnnamate moiety. J Polym Sci A, Polym Chem 30 2451-2457 Ngal T, Wu C, Chen Y (2004) Origins of the speckles and slow dynamics of polymer gels. J Phys Chem B 108 5532-5540... 

Other functional groups that can be used to form photocrosslinkable polymers are alkyne, male-imides, stilbene, styrene, 1,2,3-thiadiazole, thymine, and anthracene. Pendant groups with anthracene moiety, however, are believed to crosslink by a 47t + An type of cycloaddition ... 

Polymers containing the methyl methacrylate moiety followed by a spacer and a chalcone moiety are photocrosslinkable [30]. A chalcone contains the phenyl carbonyl ethylene phenyl sequence, or a phenyl styryl ketone. A methacrylate containing example is 4-[4[biphenyl oxy carbonyl phenyl oxy carbonyl] phenyl carbonyl ethylene phenyl] oxy butyl methacrylate. 

Preparation of photocrosslinkable co- and terpolymers of N-isopropylacrylamide, 2-(dimethylmaleimido) N-ethylacrylamide as the photosensitive component, and 3-acryloylaminopropionic acid or N-(2-(dimethylaminoethyl)- acrylamide as ionizable comonomers was reported. Here too, crosslinking takes place through formation of cyclobutane moieties ... 

Beecher et al. reported that they carried out photocrosslinking of polyurethane polymers with the aid of free-radical photoinitiators. By placing traKJ-stilbene groups in the chromophore moieties, the photocrosslinking steps are restricted to the methacryloyl double bonds, and proceed without concurrent trans-cis isomerization of the stilbene. This polymer is illustrated as follows ... 

The synthesis of unsaturated polyesters has been studied by several workers. Such materials have been used in the formation of cross-linked resins, particularly where reinforced polymers are to be used. The kinetics of the thermo-setting process has been investigated by differential scanning calorimetry. Photocrosslinkable unsaturated polyesters containing pendant chalconyl and cinnamylidenemalomyl moieties have also been produced. Such polymers were found not to exhibit any pronounced photofastness. Several other studies have described the synthesis and characterization both of the prepolymer, and the unsaturated resin. ... 

In this paper, we report the syndiesis and characterization of photocrosslinkable polymers bearing thermally degradable property 10, 11). The concept of the present system is shown in Figure 1. On irradiation network formation takes place by the photoinduced-acid catalyzed reactions of the crosslinkable moieties. A thermal treatment of the crosslinked polymers induces the cleavage of the network linkages. Based on this concept, we have... 

---