作者 Magwood, Leroy, Jr
書名 Evaluation of the physical property evolution of the hybrid acrylate/epoxide photopolymerization system
國際標準書號 9781109457339
book jacket
說明 192 p
附註 Source: Dissertation Abstracts International, Volume: 70-10, Section: B, page: 6405
Advisers: Alec B. Scranton; Chris N. Coretsopoulos
Thesis (Ph.D.)--The University of Iowa, 2009
Hybrid acrylate/epoxide photopolymerizations offer a number of advantages. Compared to each constituent homopolymerization, the hybrid systems exhibit better processing characteristics, reduced shrinkage, improved physical properties, and lower sensitivity to both oxygen and moisture. However these polymerization systems are not well understood and a systematic investigation of the influence of the photosensitizer, the monomer structure and final polymer morphology on the polymer structure and physical property development has not been previously reported. This thesis provides an improved fundamental understanding of the relationship between the polymer structure and physical property development for a spectrum of hybrid polymerizations systems of differing molecular architectures. Four representative classes of hybrid systems are examined: Case 1: A linear acrylate polymerization followed by a crosslinking cationic polymerization; Case 2: A linear acrylate capable of adding into a crosslinked epoxide; Case 3: A single monomer bearing both the acrylate and the epoxide functionality which is capable of covalent bonding into the epoxide network; Case 4: A crosslinking acrylate followed by a crosslinking epoxide. Starting the polymerization process with a linear free radical polymerization (cases 1, 2, and 3) allows shrinkage to occur without stress development (since the system can flow to alleviate the stress) and may be used to produce a stage-curable system in which reaction system moves from a liquid monomer state, to a moldable putty state before finally becoming a rigid polymer
For each type of hybrid photopolymerization system described above, the following studies were performed: the effects of the photoinitiator formulation on the conversion profile of each constituent monomer were characterized using in situ FTIR; profiles of the storage modulus and tan delta were obtained as a function of the temperature at varying compositions using DMA; the polymer morphology was characterized using SEM. In all cases, the free radical polymerization occurred more rapidly than the cationic polymerization, and the relative rates were influenced by the monomer composition and initiator formulation. The mechanical property measurements and microscopy studies revealed that the homogeneity of the final polymer increases with a thermal post cure and with the addition of a photosensitizer for some monomer compositions
School code: 0096
Host Item Dissertation Abstracts International 70-10B
主題 Engineering, Chemical
Engineering, Materials Science
0542
0794
Alt Author The University of Iowa