Click Polyester: Synthesis of Polyesters Containing Triazole Units in the Main Chain by Click Chemistry and Improved Thermal Property

Hexagonal Phase Formation and Crystalline Structural Transition in Long-Spaced Aliphatic Polyesters with Side Groups

Side substitution is an effective method for the chemical modification and functionalization of linear polyesters. The presence of side groups can have a profound effect on the crystalline structure and phase transition of semicrystalline polyesters. Herein, we synthesized the long-spaced polyesters with -OH and -CH3 side groups and various methylene segment lengths and studied the effects of the side groups on the crystal polymorph and phase transition of substituted polyesters. The substituted polyesters grow in the thermally stable phase (form I) at a higher temperature. However, the polyesters crystallize in a metastable hexagonal phase (form II) with trans chain conformation at a lower temperature. The metastable form II transforms into the more stable form I during long-time annealing or upon heating; this phase transition is accompanied by chain tilting and crystal lamellar thickening. This study has elucidated the critical role of side groups in the polymorphic crystallization and phase transition of linear polyesters.

Synthesis and Biodegradability of Tartaric Acid-Based Poly(ester-thioether)s via Thiol-Ene Click Polymerization

Using scandium triflate [Sc(OTf)₃] as a catalyst, chemoselective esterification of tartaric acids by 3-butene-1-ol was performed, and we produced three dialkene monomers: l-di(3-butenyl) tartrate (BTA), d-BTA, and meso-BTA. Thiol-ene polyaddition of these dialkenyl tartrates and dithiols including 1,2-ethanedithiol (ED), ethylene bis(thioglycolate) (EBTG), and d,l-dithiothreitol (DTT) proceeded in toluene at 70 °C under nitrogen to give tartrate-containing poly(ester-thioether)s (M_n, (4.2-9.0) × 10³; molecular weight distribution (M_w/M_n), 1.6-2.5). In differential scanning calorimetry, the poly(ester-thioether)s showed single T_gs between -25 and -8 °C. In biochemical oxygen demand (BOD) tests using activated sludge, poly(l-BTA-alt-EBTG) and poly(l-BTA-alt-ED) showed 32 and 8% biodegradability, which is comparable to that of similar l-malate-containing poly(ester-thioether)s (23 and 13% biodegradation, respectively). Notably, we observed enantio and diastereo effects on biodegradation because poly(l-BTA-alt-EBTG), poly(d-BTA-alt-EBTG), and poly(meso-BTA-alt- EBTG) showed different degradation behaviors during the biodegradation test (BOD/theoretical oxygen demand (TOD) values after 28 days, 32, 70, and 43%, respectively). Our findings provide insights into the design of biomass-based biodegradable polymers containing chiral centers.

High impact polytriazole resins for advanced composites

Three azido-terminated poly(ethylene glycol) macromonomers (ATPEGs) were synthesized from poly(ethylene glycol)s (PEGs) and characterized. The extended polytriazole (EPTA) resins were prepared from the macromonomers, azide and alkyne monomers. Toughening effect of PEGs on polytriazole resins was analyzed by means of mechanical, thermal and electronic microscope characterization. The results show that molecular weight and content of ATPEGs have great influence on the thermal and mechanical properties of cured EPTA resins. The impact strength of cured EPTA resins increases with the increase of the amount and molecular weight of ATPEGs. The flexural strength and heat resistance of cured EPTA resins decrease with the increase of addition amount and molecular weight of ATPEGs. High impact EPTA resins were obtained.

A vinyl polymer having pendent sulfones prepared by atom-transfer radical polymerization of a sulfide-containing methacrylate and electrophoretic transparent coating on a stainless-steel anode

A vinyl polymer containing pendent sulfones (oxidation > 99%), which was then selectively coated onto a stainless-steel anode by electrophoretic deposition, in which the deposited film was transparent.

Anode-selective coating of titanium(iv) oxide (TiO2) using electrophoretic sulfone-containing click polyester

We synthesized aliphatic and aromatic poly(ester-sulfide)s, via a thiol–ene click polymerization of ester-containing dialkenes with dithiols. Subsequent Oxone oxidation led to the corresponding poly(ester-sulfone). We then prepared a composite with TiO₂ using electrophoretic deposition. The composite was selectively deposited onto a stainless-steel anode.

Introducing mercaptoacetic acid locking imine reaction into polymer chemistry as a green click reaction

Some multicomponent reactions (MCRs) are similar to click reactions to give highly selective products with reliable high yield and effective atom utilization, implying that they can also be recognized as click reactions.

Synthesis of Polyethers Containing Triazole Units in the Backbone by Click Chemistry in a Tricomponent Reaction

A series of linear aromatic polyethers containing triazole units were synthesized via the direct click reaction of dibromide and bisethynyl compounds in the presence of sodium azide as one pot reaction. The structures of polymers were approved by using IR and 1H NMR techniques. The solubility experiments showed that polymers have good solubility in polar aprotic solvents such as DMSO, DMF, and NMP at higher temperatures. Thermal stability of the polymers was measured using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) which indicated that they possessed good thermal stability ( up to 558°C) and high (191.7–260°C) under N2 atmosphere. All the polymers were amorphous according to the DSC and X-ray diffraction. These polymers exhibited strong UV-vis absorption maxima near to 400 nm and up to 500 nm in DMSO solution.