研究目的
To synthesize hyperbranched polymers with disulfide bonds and vinyl groups, investigate their photocuring and reductive degradation behaviors, and evaluate their potential as reworkable curable resins.
研究成果
Hyperbranched polymers with disulfide bonds and vinyl groups were successfully synthesized and photocured. Curing at 365 nm with DMPA preserved disulfide bonds, allowing complete solubilization upon reduction with Bu3P, whereas curing at 254 nm consumed disulfide bonds and prevented solubilization. These polymers show promise as reworkable materials for applications like sealants, coatings, and adhesives, with high transparency and solvent resistance.
研究不足
The reductive decomposition did not proceed with DTT under the experimental conditions due to its susceptibility to autoxidation and lower affinity to disulfide bonds; the rate of decomposition is affected by factors like polarity and polymer backbone nature, indicating potential for optimization. Photocuring at 254 nm consumes disulfide bonds, limiting reworkability, and the study is focused on specific polymers and conditions, which may not generalize to other systems.
1：Experimental Design and Method Selection:
The study involved synthesizing hyperbranched polymers via bulk radical homopolymerization of DSDMA with MBMA as an AFCT agent, followed by photocuring using UV irradiation at 254 nm or 365 nm with or without photoinitiators, and degradation using reductants like Bu3P.
2：3P. Sample Selection and Data Sources:
2. Sample Selection and Data Sources: Polymers were synthesized from DSDMA, MBMA, and initiators like TBP or AIBN; samples were characterized using GPC, NMR, TG/DTA, DSC, and UV/Vis spectroscopy.
3：List of Experimental Equipment and Materials:
Equipment included GPC system (Tosoh CCPD RE-8020), NMR spectrometer (Bruker AN300N), TG/DTA analyzer (Seiko EXSTAR6000), DSC (Seiko EXSTAR6000), UV/Vis spectrometer (Shimadzu UV-2400), high-pressure mercury lamps (Toshiba SHL-100UVQ-2, Moritex MSU-6), UV power meter (USHIO UIT-101 with UVD-365PD receiver). Materials included DSDMA, MBMA, DMPA, Bu3P, DTT, TBP, EGDMA, AIBN, and solvents like THF.
4：Experimental Procedures and Operational Workflow:
Polymerization was carried out in sealed tubes after freeze-thaw cycles, followed by purification. Photocuring involved irradiating cast films with UV light, and degradation involved immersing samples in reductant solutions.
5：Data Analysis Methods:
Gel yield was determined by swelling tests, molecular weights by GPC with polystyrene standards, structural analysis by NMR, thermal properties by TG/DTA and DSC, and transmittance by UV/Vis spectroscopy.
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