The effect of peel angle on the peel strength was discussed by the observation of stringiness behaviorfor crosslinked poly（n-butyl acrylate-acrylic acid）with no and two different crosslinking agentcontents under constant peel load. The peel angle was varied over the range from 30 to 180°. Failuremode was cohesive failure for no crosslinked and interfacial failure for crosslinked. The stringinessshape was the sawtooth shape, but it was changed from the front frame-type to the no frame-typewith the increasing of crosslinking degree. The highest peel rate was observed at the peel angle from120 to 150°. The lower peel rate means the higher peel strength. This result indicates that the lowestpeel strength expected to be appeared in this angle range. The stress-strain curves were measured atwide strain rate range, and the obtained results were analyzed and the contour line plot of stress forwide strain and strain rate range was prepared. Using this plot, the generated stress in the fibril atthe tip of stringiness zone was calculated. As a result, the generated stress was the lowest at peelangle range from 120 to 150°. This result indicates that the peel strength is the lowest in this peelangle range. These results are in accordance with the data obtained by Kaelble［Trans. Soc. Rheology,4, 45（1960）］.

In this study, we carried out the thermolysis of poly［p-（tert-butoxycarbonyloxy）styrene]（PBSt）prepared by radical polymerization and investigated the reaction mechanism for the formation of poly（p-hydroxystyrene）accompanying the elimination of isobutene and carbon dioxide from the tert-butoxycarbonyl（Boc）group in the side chain. We also discussed the reaction conditions for thequantitative transformation of the protected functional groups in the side chain of the polymer. Theadhesion of aluminum plates using a copolymer of p-（tert-butoxycarbonyloxy）styrene and glycidylmethacrylate（P（BSt-co-GMA））with a diamine cross-linker was carried out. The lap shear testrevealed that high adhesion strength was observed for the thermally cured specimen at 100℃ for 4 h,and that the strength drastically decreased after heating at 150℃ for 1 h, due to the decompositrionof the Boc group in the copolymer.