Serial novel chiral polydiacetylenes (PDAs) are efficiently prepared at room temperature by the controllable electrophoretic deposition of diacetylenes with tunable structure as designed from easily available starting materials. The colorimetrically reversible properties of PDAs in the range between 25 and 85 °C are influenced by the different amino acid moiety in the PDAs as anticipated. The PDA containing aromatic ring is much better for the colorimetrically reversible properties, while irreversible thermochromism is displayed for the PDA with the structure of the longer methylene units in the main chain of amino acid moiety.
Directly starting from D,L-lactic acid (LA) and melamine (MA), poly (lactic acid-co- melamine) [P(LA-co-MA)] as a kind of potential polymeric flame retardant is synthesized via melt polycondensation. The properties of P(LA-co-MA) s at different molar feed ratios are characterized by XRD, DSC and TGA. Most decomposition temperatures of P(LA-co-MA) s are higher than these of homopolymer poly (D,L-lactic acid) (PDLLA). For the char yield, all copolymers have higher char yield than PDLLA. Furthermore, the more MA in the feed content, the higher char yield.
Directly using cheap D,L-lactic acid (D,L-LA) and glucose (Glu) as starting materials, biodegradable material poly(D,L-lactic acid-co-Glucose) [P(D,L-LA-co-Glu)] was synthesized via melt polycondensation. When n(Glu) : n(D,L-LA) = 1:200, the appropriate synthetic condition is that: after 120 °C prepolymerization for 5 h, 160 °C melt polymerization catalyzed by w(SnCl2) = 0.5% for 5 h. P(D,L-LA-co-Glu) with different molar feed ratios were synthesized and characterized with [η], FTIR, 1H NMR, GPC and XRD. The Tg of all copolymer P(D,L-LA-co-Glu) was lower than that of homopolymer polylactic acid directly synthesized via melt polycondensation. The copolymers with Mw from 2,100 Da to 5,100 Da could meet the demand of drug delivery carrier material.
When poly (lactic acid-co-melamine) [P(LA-co-MA)] is synthesized via direct melt polycondensation (DMP), with the more MA in the feed content, the copolymer with a three-MA-core structure linked by the ether bond is formed. Increasing the molar feed ration(LA)/n(MA), the structure of the copolymers is gradually changed from multi-core structure into SPLA structure only containing one MA core, and a peak value of Mwexists as expected. The aromatic cores with different functional groups have an important influence on the Mwpeak value, and the internal factors are the conjugate effect and the nucleophilicity caused by the different functional groups themselves.
Using flame retardant melamine (MA) as a new aromatic core, biodegradable material poly (lactic acid-co-melamine) [P(LA-co-MA)] with different molar feed ratios are synthesized via direct melt copolycondensation. The structures of P(LA-co-MA) s are characterized by FT-IR,1H-NMR,13C-NMR and GPC. The results indicate that MA moiety as the core is incorporated into the PLA backbone as expected, and the obtained products are copolymers indeed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.