The alternating copolymerization of CO₂ with the terminated epoxides anchoring long alkyl groups is rarely reported because of their low reactivity and polycarbonate selectivity. This work describes a well-controlled solvent-free copolymerization of CO₂ with 1, 2-epoxydodecane (EDD) with a long electron-donating alkyl group via the catalysis of Zn-Co(III) double metal cyanide complex catalyst. The productivity of the catalyst was up to 2406 g polymer/g Zn, that is, EDD conversion was 99.2%. The alternating degree of CO₂-EDD copolymers were more than 99% and had high number-average molecular weights (M_ns) of >100 kg mol⁻¹, while only 1.0 wt % 4-decyl-1,3-dioxolan-2-one (DC) were detected. Moreover, by introducing styrene oxide (SO) with electron-withdrawing phenyl group into EDD-CO₂ copolymerization system, a new random terpolymer with either electron-withdrawing or electron-donating side groups was produced with single glass transition temperatures (T_gs) in a wide range from 3 to 56 °C, which might be potentially used as biodegradable elastomers or plastics. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 737–744

Biodegradable poly(propylene carbonate, PPC) is a typical noncrystalline polymer from the copolymerization of carbon dioxide (CO₂) with propylene oxide (PO). But it is easy to be degraded to propylene carbonate (PC) via backbiting route during heat process (above 170°C), which limits its application. This work reports the introduction of biodegradable nanocrystalline cellulose (NCC) which was exfoliated from microcrystalline cellulose (MCC) by acid hydrolysis into PPC, affording a biodegradable PPC/NCC nanocomposite with improved thermal decomposition temperatures (the initial decomposition temperature, T_5wt% was up to 265°C). Impressively, the thermal decomposition of PPC to PC at 200°C within 4.0 h was dramatically inhibited by introducing NCC, which was evident by ¹H NMR spectra. This could be attributed to the hydrogen bonding interaction between NCC and PPC. Moreover, the film of PPC/NCC nanocomposite had not deformed when it was heated at 110°C for 4 h. In application, such biodegradable nanocomposite is a promising disposable package material. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39847.

Although zinccobalt (III) double metal cyanide complex (ZnCo (III) DMCC) catalyst is a highly active and selective catalyst for carbon dioxide (CO₂)/cyclohexene oxide (CHO) copolymerization, the structure of the resultant copolymer is poorly understood and the catalytic mechanism is still unclear. Combining the results of kinetic study and electrospray ionization-mass spectrometry (ESI-MS) spectra for CO₂/CHO copolymerization catalyzed by ZnCo (III) DMCC catalyst, we disclosed that (1) the short ether units were mainly generated at the early stage of the copolymerization, and were hence in the “head” of the copolymer and (2) all resultant PCHCs presented two end hydroxyl (OH) groups. One end OH group came from the initiation of zinchydroxide (ZnOH) bond and the other end OH group was produced by the chain transfer reaction of propagating chain to H₂O (or free copolymer). Adding t-BuOH (CHO: t-BuOH = 2:1, v/v) to the reaction system led to the production of fully alternating PCHCs and new active site of ZnOt-Bu, which was proved by the observation of PCHCs with one end Ot-Bu (and OCOOt-Bu) group from ESI-MS and ¹³C NMR spectra. Moreover, Zn−OH bond in ZnCo (III) DMCC catalyst was also characterized by the combined results from FT-IR, TGA and elemental analysis. This work provided new evidences that CO₂/CHO copolymerization was initiated by metalOH bond. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

Inherently flame retardant epoxy resin is a kind of halogen-free material for making high-performance electronic materials. This work describes an inherently flame retardant epoxy system composed of 4,4′-diglycidyl (3,3′,5,5′-tetramethylbiphenyl) epoxy resin (TMBP), 1,2-dihydro-2-(4-aminophenyl)-4-(4-(4-aminophenoxy) phenyl) (2H) phthalazin-1-one (DAP), and hexa(phenoxy) cyclotriphophazene (HPCTP). The cure kinetics of TMBP/DAP in the presence or absence of HPCTP were investigated using isoconversional method by means of nonisothermal differential scanning calorimeter (DSC). Kinetic analysis results indicated that the effective activation energy (E_α) decreased with increasing the extent of conversion (α) for TMBP/DAP system because diffusion-controlled reaction dominated the curing reaction gradually in the later cure stage. TMBP/DAP/HPCTP(10 wt %) system had higher E_α values than those of TMBP/DAP system in the early cure stage (α < 0.35), and an increase phenomenon of E_α ∼ α dependence in the later cure stage (α ≥ 0.60) due to kinetic-controlled reaction in the later cure stage. Such complex E_α ∼ α dependence of TMBP/DAP/HPCTP(10 wt %) system might be associated with the change of the physical state (mainly viscosity) of the curing system due to the introduction of HPCTP. These cured epoxy resins had very high glass transition temperatures (202–235°C), excellent thermal stability with high 5 wt % decomposition temperatures (>340°C) and high char yields (>25.6 wt %). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

A bismaleimide monomer, 4,4′-bis(4-maleimidophenoxy)-3,3′,5,5′-tetramethyl biphenyl (BMITB), was synthesized in high yield (94%) via a facile four-step reaction from 2,2′,6,6′-tetramethyl-4,4′-biphenol. The chemical structure of BMITB was confirmed by FTIR, ¹H NMR, ¹³C NMR and elemental analysis. The monomer used to modify the epoxy cresol-formaldehyde novolac resin (ECN)/diaminodiphenyl sulfone (DDS) system. Cured ECN/BMITB/DDS blends with higher BMITB content had two distinct glass transition temperatures that were above 250°C according to differential scanning calorimetry, indicating that an interpenetrated polymer network structure may be formed. The initial thermal decomposition temperature and integral procedure decomposition temperature of the cured ECN/BMITB/DDS blends were >390 and 1080°C, respectively, according to thermogravimetric analyses. No phase separation was observed in dynamic mechanical analysis of cured ECN/BMITB/DDS blends with small amounts of BMITB (5 and 10 wt%). POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers

Air-stable hybrid catalysts of silicon dioxide/double metal cyanide complexes (Si-DMCCs) based on Zn₃[Co(CN)₆]₂ (ZHCC) were prepared by an in situ sol–gel method. The Si-DMCCs showed low crystallinity and a nanolamellar structure with a thickness of ∼40–60 nm. In particular, a lamellar structure of regular hexagonal shape was observed for Si-DMCCs with low SiO₂ content. These catalysts had very high catalytic activity for alternating copolymerization of cyclohexene oxide (CHO) and carbon dioxide. A turnover number of 11,444, turnover frequency of 3815 h⁻¹, and apparent efficiency of 7.5 kg polymer/g ZHCC (∼24.0 kg polymer/g Zn) were achieved at 3.8 MPa and 100 °C. The poly(cyclohexenylene carbonate) (PCHC) polymers obtained were completely atactic with a molecular weight (M_n) of ∼10 kg/mol and polydispersity of 2.0–3.0. The PCHCs had a structure of nearly alternating CHO and CO₂ units, with a molar fraction of carbonate units of 0.44–0.47. Preliminary investigations of the mechanism suggest that nucleophilic attack by neighboring oxygen atoms is involved in copolymerization initiation with ZnCo^III DMCCs. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3128–3139, 2008