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A structure property investigation of a multi-component polyacrylate photoresist
Abstract
The multi-component acrylate photoresist investigated in this dissertation consists of a linear polyacrylate copolymer, a photo-polymerizable multi-functional acrylate monomer, a ketone photo-initiator, an amine crosslinking agent and a certain amount of inorganic filler. Three distinct phases have been observed in this multi-component system by transmission electron microscopy (TEM)--the flake-like inorganic filler, the monomer-rich droplet inclusion and the polymer-rich matrix. Selected area diffraction (SAD) has determined the crystalline structure of the filler phase and the amorphous structure of the matrix phase. It has also concluded that the diffraction rings in the monomer-rich inclusion phase come from the filler polycrystals. After the photoresist is fully cured by UV radiation followed by thermal baking, distinct spots in the dimension of 100 A have been observed in the monomer-rich inclusion phase. The subsequent thermal curing process increases the mobility of the molecules and provides sufficient time for the molecules to aggregate and form distinct micro-phases in the monomer-rich inclusions. In the mean time, the filler crystals grow larger and distinct diffraction rings and spots can be seen in the SAD pattern. In contrast to the phase-separate morphology of the multi-component photoresist, only one broad glass transition has been observed by DSC, DMA and dielectric relaxation experiments. The broad glass transition reflects the inhomogeneity of local composition and the heterogeneous network structure of the material. The structure-property relationship of the multi-component photoresist as a function of curing history has been investigated. The residual stress and mechanical properties of the acrylate photoresist processed under various curing conditions have been characterized, and the curing mechanism has also been investigated. The increased glass transition temperature, modulus and ultimate strength of the material indicate that either ultraviolet radiation or thermal baking partially cures the photoresist. However, FTIR studies suggest that the two curing methods generate different network structures through independent crosslinking mechanisms. Both curing methods are required to fully cure the acrylate photoresist and achieve the desired coating properties. It has been found that the curing sequence plays an important role in determining the final network structure and material properties of the thermoset coating. (Abstract shortened by UMI.)
Subject Area
Polymer chemistry|Packaging|Plastics
Recommended Citation
Tong, Quinn Kun, "A structure property investigation of a multi-component polyacrylate photoresist" (1993). Doctoral Dissertations Available from Proquest. AAI9329677.
https://scholarworks.umass.edu/dissertations/AAI9329677