Adipic Bis Research Articles

Self-regenerating zwitterionic hyperbranched polymer with tunable degradation for anti-biofouling coatings

Regeneration of zwitterionic surfaces is a promising strategy to combat biofouling. In this study, we have prepared degradable hyperbranched anti-biofouling polymers of methyl methacrylate, tertiary carboxybetaine ester (TCB), and divinyl monomers via reversible addition-fragmentation chain transfer (RAFT) polymerization. The degradation rate of such polymers is a function of the content or type of divinyl monomers. As the content of methacrylic anhydride (MAAH) increases, the degradation rate of the polymer becomes faster; whereas, a change of the divinyl monomers causes the degradation rate to follow a descending order: N,N′-adipic bis(diacetone acrylamide hydrazone) (DAA2H) > MAAH > ethylene glycol dimethacrylate (EGDMA). Antibacterial and anti-diatom assays show that the coatings inhibit the adhesion of the marine bacteria Pseudomonas sp. and the diatom Navicula incerta. The polymeric coating is expected to be applied in marine anti-biofouling.

Synthesis and Performances of Hydrocinnamic Acid Derivatives Containing Alkyl Dihydrazide

In this work, four hydrocinnamic acid derivatives including N, N’-succinic bis(hydrocinnamic acid) dihydrazide (HASUD), N, N’-adipic bis(hydrocinnamic acid) dihydrazide (HAADD), N, N’-sebacic bis(hydrocinnamic acid) dihydrazide (HASED) and N, N’-dodecanedioic bis(hydrocinnamic acid) dihydrazide (HADOD) were synthesized via two liquid reactions. And then fourier transform infrared spectrometer and 1H nuclear magnetic resonance were used to characterize molecular structures of four hydrocinnamic acid derivatives. Additionally, the orthogonal experiment obtained the optimum synthesis process of four hydrocinnamic acid derivatives, and the maximum yield of HASUD, HAADD, HASED and HADOD were 33.3%, 43.2%, 43.5% and 51.9%, respectively. DMol3 was used to optimize geometric structure and obtain frontier orbital energy. Finally, hydrocinnamic acid derivatives and poly(L-lactide) (PLLA) were blended using the torque rheometer to investigate these role in PLLA resin. The resultant from the melt-crystallization process showed that hydrocinnamic acid derivatives as heterogeneous nucleating agents could significantly enhance PLLA’s crystallization.

Non-isothermal Crystallization, Melting Behavior, Thermal Decomposition, Fluidity and Mechanical Properties of Melt Processed Poly(L-lactic acid) Nucleated by N,N'-Adipic Bis(piperonylic acid) Dihydrazide

Enhancing on the crystallization ability of poly(L-lactic acid) (PLLA) during practical processing is one of the most effective way to overcome the poor heat resistance. In this work, N,N '-adipic bis(piperonylic acid)dihydrazide (PAAH) was synthesized to be firstly used as a heterogeneous nucleating agent to evaluate its influence on the performances, including the crystallization, melting behavior, thermal stability, fluidity and mechanical property, of PLLA. The nucleation effect of PAAH was determined via the melt-crystallization of PLLA with various PAAH concentrations from 0.5 to 3 wt % at different cooling rates, as well as the different final melting temperature Tf . The results revealed that the PAAH could significantly accelerate the crystallization of PLLA in cooling, and the melt-crystallization peak shifted toward the higher temperature with increasing of PAAH concentration, resulting from an increase of nucleation density in PLLA matrix. Additionally, both the cooling rate and Tf were two critical factors to crystallization, a higher cooling rate could weaken the crystallization ability of PLLA/PAAH, and the 200°C was the optimum melting process temperature. For cold-crystallization, PAAH had an inhibition for the cold-crystallization of PLLA, but the cold-crystallization peak moved toward the higher temperature with increasing of heating rate because of thermal inertia. There existed only a single melting peak after melt-crystallization at cooling of 1°C, which further confirmed the advanced nucleation effect of PAAH, but the double-melting peaks appeared after isothermal crystallization at 110°C, which was attributed to the melt-recrystallization. The other measurements showed that, compared to the neat PLLA, the addition of PAAH decreased the thermal stability and tensile modulus of PLLA, but PLLA/PAAH samples had the better fluidity, the higher tensile strength and the longer elongation at break.

Heterogeneous Nucleation Effect of N, N'-Adipic Bis(4-phenylbutyric Acid) Dihydrazide on Crystallization Process of Poly(L-lactic Acid)

Enhancing crystallization ability is a fundamental challenges in Poly(L-lactic acid) (PLLA) industry, therefore, the goal of this work was to synthesis a new organic nucleating agent N, N'-adipic bis(4-phenylbutyric acid) dihydrazide (APAD), and investigate its effect on non-isothermal crystallization, isothermal crystallization, melting behavior, thermal stability, and optical property of PLLA. Non-isothermal melt crystallization results showed that APAD acted as more effective nucleating and accelerating agent for the crystallization of PLLA, as a result, upon cooling at 1 °C/min, PLLA/0.5 %APAD had the highest onset crystallization temperature 136.4 °C and the crystallization peak temperature 132.0 °C, as well as the largest non-isothermal crystallization enthalpy 48.1 J/g. However, with increasing of APAD concentration from 0.5 wt.% to 3 wt.%, the crystallization peak shifted to the lower temperature. In contrast, for the non-isothermal cold crystallization process, the effect of APAD concentration on the crystallization behavior of PLLA was negligible. Additionally, the non-isothermal crystallization process was also depended on the cooling rates and the final melting temperature. In isothermal crystallization section, to compare with the primary PLLA, the crystallization half-time of PLLA/APAD could decrease from 254.3 s to the minimum value 29.4 s, with 0.5 wt.% APAD contents at 125 °C. Melting behavior of PLLA/APAD samples under different conditions further confirmed the heterogeneous nucleation effect of APAD for PLLA, and the appearance of the double melting peaks was attributed to the melting-recrystallization. Finally, the addition of APAD decreased the thermal stability to some extent, although APAD could not change the thermal decomposition profile of PLLA. And a drop of PLLA/APAD samples in light transmittance resulted from the double influence of the enhancement of crystallization and the opaqueness of APAD.

Investigation on the modification of N,N′-adipic bis(benzoic acid) dihydrazide on poly(l-lactic acid)

In this study, poly(l-lactic acid) (PLLA) modified using N,N′-adipic bis(benzoic acid) dihydrazide (BAAD) was fabricated by melt blending technology, and the differential scanning calorimetry, optical depolarizer, and thermogravimetric analysis (TGA) evaluated the effects of BAAD on crystallization behavior, melting behavior, and thermal stability of PLLA. Non-isothermal crystallization behavior indicated that BAAD as a heterogeneous nucleating agent had excellent acceleration effectiveness on the melt crystallization process of PLLA; however, an increase in cooling rate weakened the crystallization promoting effect of BAAD for PLLA, resulting from increasing cooling rate which led to decrease in the nuclei density. Additionally, non-isothermal crystallization results revealed that the effect of the final melting temperatures on the crystallization peak temperature and crystallization enthalpy was negligible. Isothermal crystallization measurement showed that the minimum t1/2 of the primary PLLA appeared at 120 °C, but the PLLA/2%BAAD exhibited the shortest t1/2 of 33.9 s at 95 °C comparing to the primary PLLA and other PLLA/BAAD samples. Through the analysis of the frontier molecular orbital energy and thermal stability of PLLA/BAAD system, it was proposed that the nucleation mechanism of the PLLA/BAAD system was chemical nucleation. Melting behavior of PLLA/BAAD system further confirmed the crystallization accelerating effect of BAAD for PLLA, as well as that the melting behavior of a given sample after non-isothermal crystallization was almost not dependent upon the heating rates, but the melting peak after isothermal crystallization shifted toward the higher temperature with the increase in crystallization time. Finally, the results of TGA measurements indicated that BAAD could not change the thermal decomposition profile of PLLA, but the concentration of BAAD could affect the onset decomposition temperature of PLLA.

Ladder-chain zinc coordination polymers based on adipic acid dihydrazide precursor: Synthesis and structural transformations

Two ladder-chain zinc coordination polymers were synthesized in aqueous or N,N-dimethylformamide (DMF) solution by use of adipic acid dihydrazide (adih) precursor: {[Zn2(H2aph)(pim)2]·4H2O}n (pim=pimelate, H2aph=adipic bis(2-picolinylidene)hydrazide) and {[Zn2(adih)3][NO3]4·2DMF}n. X-ray crystal structures of the polymers were determined and the lattice solvent removal was investigated. The structural, spectroscopic and thermogravimetric studies confirm reversible and irreversible transformation upon desolvation for the former and latter 1D chains, respectively. The details of the reversible dehydration and rehydration are revealed by powder X-ray structure elucidation of the desolvated phase and are corroborated by IR spectroscopy.

Synthesis of polyamides from linear bisanhydrides and diamines

AbstractThe aminolysis of benzoic mesitoic anhydride was studied in a model system to select the reaction site by steric effect and was found to occur exclusively at the carbonyl group of the benzoic acid. Solution polycondensation of new linear bisanhydrides, terephthalic bis(mesitoic anhydride) and adipic bis(mesitoic anhydride), with aromatic diamines in polar aprotic solvents that contained lithium chloride at room temperature, afforded polyamides with high molecular weight. The interfacial polycondensation in a dichloromethane‐water system also successfully yielded polyamides from aliphatic diamines.