RSC Advances
·
2016
·Vol. 6
·期 16
·13418-13425
·
IF 3.289
Fubin Luo,Kun Wu,Mangeng Lu
The influence of polybenzoxazine modified ammonium polyphosphate (BMAPP) on the thermal behavior and flame retardancy of a rigid polyurethane foam (PU) are investigated via thermogravimetric analysis (TG), TG coupled with infrared spectroscopy (TG-FTIR), UL-94 vertical burning testing and limit oxygen index (LOI). The TG testing results indicate that BMAPP can enhance the thermal stability of PU, both under air and nitrogen conditions. The initial degradation temperature of the BMAPP/PU composites is 264 °C in air, which is 22 °C and 30 °C higher than that of ammonium polyphosphate (APP)/PU composites and neat PU, respectively. The reason might be attributed to the better dispersion and compatibility of BMAPP particles in PU compared with APP, which can prevent the PU chain from degrading at low temperatures. The LOI value results demonstrate that BMAPP has higher flame retardancy in PU than APP. Residue analysis implies that polybenzoxazine is partially converted into Si–O as char residue during combustion.
研究领域:
高分子材料科学
·
阻燃材料
·
热功能材料
·
复合材料学
·
材料化学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2015
·Vol. 3
·期 44
·22136-22144
·
IF 7.443
Renzhong Zhang,Xueqin Wang,Jun Song,Yang Si,Xingmin Zhuang,Jianyong Yu,Bin Ding
Construction of nanoparticle modified titanium dioxide nanofibrous membranes (TiNFs) with a mesoporous and stable nanoparticle-nanofiber composite structure would have significant implication for environmental remediation; however, currently nanoparticle-TiNFs are generally brittle with poor structural integrity upon large deformation; thus, creating flexible, robust, and stable nanoparticle-TiNF composites has proven to be extremely challenging. Herein, we report flexible and hierarchical mesoporous TiO2 nanoparticle (TiO2 NP) modified TiNF (TiNFNPs) composites fabricated by the combination of sol–gel electrospinning and in situ polymerization. The electrospun TiNFs served as templates and a synthesized bifunctional benzoxazine (BA-a) was used as a novel carrier and fixative for non-agglomerated growth of TiO2 NPs. Benefiting from the large surface area, high porosity, homogeneity, stable nanofiber–nanoparticle composite structure, and robust mechanical properties, the as-prepared anatase TiNFNPs exhibited excellent photocatalytic activity towards methylene blue including fast degradation within 30 min, good reversibility in 4 cycles, and easiness of recycling. Moreover, the degradation products have been analysed and TiNFNPs exhibited better photodegradation performance towards methylene blue compared with a commercial catalyst (P25). Significantly, the successful synthesis of such fascinating materials may provide a versatile platform for further development of nanofibrous membrane-based photoreactors towards water and air pollutant treatment.
研究领域:
材料科学
·
环境修复
·
纳米技术
·
光催化
·
高分子科学
✓ 已验证
DOI
高影响因子
POLYMER BULLETIN
·
2023
·Vol. 81
·期 6
·5403-5420
·
IF 3.2
Liu Jiamei,Yang Rui,Sheng Weichen,Zhang Kan
Aromatic polyimides have attracted wide attentions in fields of aerospace, microelectronics and defense applications due to their outstanding thermal and mechanical performances. However, the rigidity originating from the imide structure attached with an aromatic ring causes difficulties in processing. In this study, we synthesized two ortho- phthalimide functional benzoxazine monomers with additional cross-linkable groups (including both furan and alkynyl). An ortho- phthalimide functional phenol, 2-(2-hydroxyphenyl) isoindole-1,3-dione ( o PP), was obtained by reacting o -aminophenol and phthalic anhydride in acetic acid. Two monofunctional ortho- phthalimide containing benzoxazine monomers ( o PP-fa and o PP-pa) were then synthesized using the Mannich reaction based on raw materials of o PP, furfurylamine/propargylamine and paraformaldehyde in toluene. The structures of benzoxazine monomers were confirmed by FT-IR and 1 H NMR spectroscopies. We also investigated effects of cross-linkable functionalities on curing behaviors as well as their corresponding polymerization mechanisms. The activation energies of o PP-fa and o PP-pa were calculated by Kissinger and Ozawa equations based on DCS measurements with different heating rates. It demonstrates that the exothermic peak temperature of o PP-pa is located at 178.5 °C, which is much lower than that of o PP-fa (223.3 °C). The alkyne group in o PP-pa plays a catalytic effect role in reducing the ring-opening polymerization temperature of the oxazine ring. Moreover, the thermogravimetric analyzer (TGA) was used to evaluate thermal properties of the obtained polybenzoxazine thermosets. Both thermosets exhibited improved thermal stability compared with some other reported monobenzoxazine-derived polybenzoxazines.
研究领域:
高分子科学
·
材料化学
·
热分析
·
有机合成
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2017
·
IF 6.216
Shiyuan Chen,Junheng Zhang,Jiliang Zhou,Daohong Zhang,Aiqing Zhang
A novel hyperbranched polymeric ionic liquid (HBP-AMIM + PF6 − ) was explored via a thiol-ene click reaction using thiol-ended hyperbranched polyesters (THBP) and 1-allyl-3-imethylimidazolium hexafluorophosphate (AMIMPF6). The effects of HBP-AMIM + PF6 − on the curing behavior, mechanical properties and thermal stability of benzoxazine/epoxy thermosets were investigated. The gelation time and differential scanning calorimetry of non-isothermal analysis indicated that the addition of HBP-AMIM + PF6 − significantly decreased the curing temperature of benzoxazine/epoxy thermosets. Simultaneously, the addition of HBP-AMIM + PF6 − also improved the strength, toghness and thermal properties of benzoxazine-epoxy thermosets. The addition of 3 wt% HBP-AMIM + PF6 − -2 could significantly improve the mechanical and thermal performance of thermosets compared with that of cured neat benzoxazine/epoxy resin. The tensile strength, tensile toughness, flexural strength and flexural modulus, impact strength of the thermosets were improved by about 76.6%, 279.3%, 57.8%, 22.3% and 80.4%, respectively, compared with those of cured neat resin. The toughening mechanisms was attributed to the “in situ” reinforcing and toughening mechanism.
研究领域:
高分子材料
·
材料科学
·
热固性树脂
·
复合材料
·
高分子化学
·
功能材料
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）