19389-82-3Relevant academic research and scientific papers
Macromolecular chain structure design, synthesis and analysis of poly(l-lactide) linking ultraviolet absorbing groups
Ge, Feijie,Huang, Yun,Luo, Yu,Jiang, Long,Dan, Yi
, p. 63118 - 63127 (2014)
Poly(l-lactide) (PLA) with different chain structures was designed, and successfully synthesized by ring opening polymerization using 2-hydroxy-4-(3-methacryloxy-2-hydroxylpropoxy) benzophenone (BPMA), 2,2′-dihydroxy-4,4′-(2-hydroxylpropoxy) dibenzophenone (DHDBP) and 2-hydroxy-4-(2,3-dihydroxylpropoxy) benzophenone (HPBP) as initiators, respectively, to produce corresponding PLA-B (end-capped with BPMA), PLA-DB (end-capped with DHDBP) and PLA-HB-PLA (blocked with HPBP in the middle). High-molecular-weight PLA-DB400 with good visible light transparency and UV opacity was prepared. The chemical structures of the samples were characterized, the crystallization behavior, thermal stability, UV absorption properties and transmittance of PLA were investigated and analyzed. Results of GPC and DSC reveal that when the number average molecular weights (Mn) of PLA are around 4000, termination of a UV absorbing group like DHDBP greatly restricts the crystallization of PLA due to the larger volume and rigidity of the end-capping group, but increasing Mn to about 12000 or higher weakens the hindering effect, resulting in a similar degree of crystallization (Xc). TG results show that PLA-DB400 has the best thermal stability due to the highest molar mass. When the UV absorber is blocked in the PLA chain, the restriction and steric hindrance of the absorber are much stronger than that in the end-capped material, making Xc significantly reduced. UV absorbance of the PLA solutions reveals that the introduction of UV absorbing groups gives an absorption to UV light below 350 nm and the position of the introduced groups has no influence on the UV absorption properties although the content of the UV group does enhance the UV absorbance, of which PLA-DB has the highest since DHDBP bears two 2-dihydroxybenzophenone groups. The transparency of PLA films is neither affected by position nor content of the introduced UV absorbing groups, which is very beneficial for the application of PLA in packaging materials that require high transparency.
Benzophenone derivative, ultraviolet absorbent and external preparation for skin
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, (2008/06/13)
Benzophenone derivatives expressed by the following general expression (1): wherein A in the above general expression (1) is a residual group obtained by removing one hydroxyl group from sugar or sugar alcohol, and B is a benzophenone group shown by the following general expression (2) STR1 wherein R1 through R10 each is expressed by hydrogen, hydroxyl group, an alkoxy group, or the aforesaid binder C, and at least one of them is the binder C. In the case of an alkoxy group, preferably the number of carbon atoms is 1 to 4. C is equivalent to --O--R-- (O is oxygen, R is a fatty chain, and the number of carbon atoms therein is preferably 1 to 4), or 1 mole of glycerin with one hydroxyl group therein bound to A and another hydroxyl group to B. The benzophenone derivatives according to the present invention have excellent capability to absorb ultraviolet rays as well as high compatibility with polar solvent. Also the external preparation for skin in which the benzophenone derivatives are mixed can be mixed in a polar base with wide availability for industrial purpose.
