POLYMER DEGRADATION AND STABILITY
·
2022
·
IF 5.204
Shuang-Lin Hu,Ying-Ming Li,Wen-Juan Hu,Jose Hobson,De-Yi Wang
Unsaturated polyester resin (UPR) composites with excellent flame retardancy and high mechanical property is a great challenge to its widely application. In present work, a highly efficient flame retardant (MA-DOPO) containing nitrogen, sulfur and phosphorus elements was designed via a nucleophilic substitution reaction of amino and aldehyde groups. For the UPR/MA-DOPO 15 composites, its tensile strength was 28.3 MPa, which was 19.9 % higher than that of neat UPR attributing to the formation of hydrogen bonds with UPR. It should be noted that tensile strength of UPR/MA-DOPO 20 composites reached the highest 39.6 MPa, showing a growth trend with the enhancement of incorporation amount of MA-DOPO. Meanwhile, the UPR/MA-DOPO 15 composites passed the UL-94 V-0 rating with a LOI of 27.0%, and the peak heat release rate (PHRR) and total heat release rate (THR) were reduced by 35.1% and 41.6% in cone calorimeter (CC) test comparing to that of neat UPR respectively. Moreover, the detailed flame-retarding mechanism of MA-DOPO was investigated by the thermogravimetric infrared spectroscopy (TG-IR), Raman spectrum, X-ray photoelectron spectroscopy (XPS) and pyrolysis-gas chromatography/mass spectrometry (PY-GC/MS), in which the releasement of inert gas in gas-phase and the catalytic carbonation in condensed phase jointly taking effect.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2024
·
IF 6.3
Tong-Yu Bai,Xiang-Xin Xiao,Guan-Qi Zheng,Qin Zhang,Zi-Ni Wang,Li Chen,Bo-Wen Liu,Yu-Zhong Wang
Polycarbonate is a widely used engineering plastic material, but its limited flame retardancy has restricted its application in high-end fields such as aviation and railways. In this study, we propose a novel copolymerization/macromolecular blending strategy to produce a high-performance, fire-safe polycarbonate composite. By copolymerizing with polydimethylsiloxane oligomer and blending with macromolecular polyarylate, the resulting PC-BPDMS 5 /PITR successfully achieved a UL-94 V-0 rating and a high limiting oxygen index value of 34.2%. The peak heat release and total smoke release were significantly reduced by 45.2% and 27.4%, respectively, compared to pure PC. SEM, Raman, and XPS analyses confirmed the condensed-phase dominated flame-retardant mechanism, attributed to the char-forming ability of the polyarylate and polydimethylsiloxane segments. Polydimethylsiloxane segments can decompose to produce small molecules such as methane, and the left structure with silicon, which undergo cross-linking reactions with the substrate during combustion to promote char formation. The polyaromatic ring structure of PITR can also participate in the formation of a dense and stable char layer. The excellent compatibility between the polyarylate and the PC matrix, combined with the superior flexibility of polydimethylsiloxane, allowed the composite to maintain mechanical properties comparable to pure PC. Additionally, the increased molar volume resulted in a low dielectric constant for PC-BPDMS 5 /PITR. This work presents a promising approach for the development of high-performance polycarbonate composites.
研究领域:
材料科学
·
聚合物化学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2014
·
IF 2.633
Liqiang Gu,Guoan Chen,Youwei Yao
Two novel halogen-free flame retardants , DP-DDE and DP-DDS, were synthesized via a one-pot procedure based on the Pudovik reactions between 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) and imines directly resulting from the condensation reactions of 3-methoxy-4-hydroxybenzaldehyde with two typical curing agents , 4,4′-oxydianiline (DDE) and 4,4′-diaminodiphenylsulfone (DDS), respectively. The fire-resistant properties of DP-DDE or DP-DDS modified epoxy resins (2,2-bis(4-glycidyloxyphenyl)propane) with 4,4′-methylenedianiline as hardener were been investigated by UL-94 vertical test. Their high flame-retarding performance has been found: the epoxy thermosets with a relatively low addition amount of DP-DDE or DP-DDS (on the account of phosphorus content of 0.75 wt.% or 0.73 wt.%) can reach UL-94 V-0 flammability rating. These thermosets demonstrated excellent thermal stability, high glass transition temperature ( T g > 135 °C) and high char yields (>22% at 800 °C). Moreover, the thermal degradation kinetics of the flame retardants and their corresponding epoxy thermosets were studied based on Kissinger, Ozawa and FWO methods by thermogravimetric analysis .
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Peng Lu,Ze-Yong Zhao,Bo-Ren Xu,Ying-Ming Li,Cong Deng,Yu-Zhong Wang
Thermoplastic polyamide elastomers (TPAEs) are a new and important member of the thermoplastic polymer elastomers (TPEs) family, and the flame retardation of TPAEs is a big challenge due to the deterioration of their properties. In this work, we have successfully designed and synthesized the first “inherently” flame-retardant TPAE by introducing a phosphorus-containing group (DDP) into the macromolecular chains through P-C covalent bonds. The properties of TPAEs can be regulated by controlling the contents and distribution of polyamide (PA) segments as a hard segment, polyethylene glycol (PEG) as a soft segment, and DDP as a flame retardant unit during the synthetic process. The resulting TPAEs can achieve a V-0 rating in the UL-94 test and a limiting oxygen index of higher than 35.0%. The enhancement of flame retardancy is attributed to the droplet-promoting mechanism and the free radical quenching effect in the vapor phase. Unfortunately, the density of the inter-chain H-bonding and crystallinity of the PA segments regions decreased with the incorporation of DDP groups, which lead to the decrease of the tensile properties of TPAEs. However, the samples with high flame retardancy are still able to maintain 400% of elongation at break and 20 MPa of tensile strength, respectively, which have better comprehensive properties than typical commercial TPEs (Pebax®). Therefore, this novel inherently flame-retardant thermoplastic polyamide elastomer will exhibit a wider range of application potentials.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
·
2015
·Vol. 26
·期 3
·255-265
·
IF 1.757
Xuan Zhou,Juan Li,Yonggang Wu
Aluminum hypophosphite (AHP) was introduced into polylactide/intumescent flame retardant (PLA/IFR) systems by melt blending. The flame retardant and thermal properties of the PLA composites were investigated. The results suggest that a synergistic effect exists between IFR and AHP on the char formation and anti-dripping behavior of PLA composites. The PLA/IFR composites containing 10 wt% IFR can pass the UL-94 V-0 rating but the test is accompanied by heavy melt dripping. For the PLA/AHP a UL-94 V-2 rating is obtained for the same loading of IFR. However, the composites containing 7 wt% IFR and 3 wt% AHP pass the UL-94 V-0 rating with modified dripping behavior. Moreover, the char from combustion of PLA/IFR is flexible but of poor quality. That for PLA/AHP is brittle with many cracks. In contrast, that for PLA/IFR/AHP is strong and compact. Thus it can resist the erosion due to heat and gas formation and protect the inside of the matrix. In addition, AHP causes the crosslinking among APP, which promotes the char formation and prevents the melt dripping. This is the main reason for the good flame retardant properties of PLA composites. Copyright © 2015 John Wiley & Sons, Ltd.
研究领域:
材料科学
·
阻燃材料
✓ 已验证
产品关联
DOI
高影响因子
FIRE SAFETY JOURNAL
·
2020
·
IF 2.295
Qianqian Zhang,Jun Wang,Shuang Yang,Jianwen Cheng,Guoping Ding,Yefa Hu,Siqi Huo
In order to meet the requirement in the fields with high flame resistance, the flame retardancy of epoxy resin (EP) must be ameliorated. Herein, a P/N/S-based flame retardant (PAD) was synthesized and used to prepare flame retardant EP. The combustion behavior, thermal property and flame retardant mechanism of the prepared EP thermosets were investigated. PAD induced the decomposition of EP thermoset in advance. Meanwhile, PAD enhanced the flame retardance of EP thermosets and reduced the fire risk of EP matrix. For example, with only 0.5 wt% phosphorus, EP/DDS/PAD-0.5 easily passed UL-94 V-0 rating and achieved a LOI value of 33.6%, together with the declined heat release rate (HRR). Impressively, the glass transition temperature (T g ) of EP/DDS/PAD thermosets dropped by only 3–13 °C, compared with that of EP/DDS. During combustion, PAD prompted the formation of an intumescent char layer in condensed phase, and exerted blowing-out effect in gaseous phase .
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2017
·Vol. 52
·期 24
·13992-14003
·
IF 2.599
Xiao Fei,Wu Kun,Luo Fubin,Guo Yuyue,Zhang Shiheng,Du Xiangxiang,Zhu Qingqing,Lu Mangeng
In order to develop a highly efficient flame-retardant system, a phosphonate-based ionic liquid named 1-vinyl-3-(diethoxyphosphoryl)-propylimidazolium bromide (IL) was synthesized and introduced into epoxy resin (EP). With only 4 wt% loading, EP/IL composite passed UL-94 V-0 rating, and its limiting oxygen index value increased to 34.9% from 25.9% for neat epoxy resin. The char yield of EP/IL-2 (2 wt%) was improved by 58.3%, and its peak of heat release rate was reduced by 65% compared with that of neat EP. The reason is that the presence of IL promoted the forming of a compact and stable phosphorus-rich residual chars. Unlike traditional additive-type flame retardant, it is very interesting that the introduction of IL changed the color and transparency of EP few and enhanced mechanical property of neat EP remarkably. Owing to the excellent compatibility and steric effect between IL and EP matrix, tensile strength was increased to 108.6 MPa for EP/IL sample from 84.9 MPa for neat EP, indicating the outstanding reinforcement effect of IL on EP composites.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2016
·
IF 2.567
Chao Ma,Bin Yu,Ningning Hong,Yang Pan,Weizhao Hu,Yuan Hu
A novel branched poly(phosphonamidate-phosphonate) (BPPAPO) oligomer was synthesized from the polycondensation of phenylphosphonic dichloride and trihydroxymethylphosphine oxide followed by end-capping with aniline in a one-pot synthesis. BPPAPO exhibited excellent flame-retardant efficiency in epoxy resins (EP). With only 5.0 wt % loading, the EP composite reached UL-94 V-0 rating with a limiting oxygen index (LOI) value of 35.5%. BPPAPO catalyzed the early degradation of EP and promoted the formation of more char residue. Glass transition temperatures were partially lowered. When 7.5 wt % BPPAPO was incorporated, the peak heat release rate and total heat release were decreased by 66.2% and 37.3%, respectively, with a delayed ignition and the formation of a highly intumescent char residue. Combination of gas-phase and condensed-phase flame-retardant mechanisms was verified.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2024
·Vol. 17
·期 3
·761
·
IF 3.1
Yanli Dou,Aixun Ju,Zheng Zhong,Yutong Huo,Weiguo Yao
Unsaturated polyester resin (UPR) with excellent flame retardant is mainly obtained by adding large amounts of flame retardants, usually at the expense of mechanical properties. In this work, a reactive flame retardant containing phosphorus and nitrogen (DOPO-N) was successfully synthesized and incorporated in UPR as a crosslinker. The mechanical and flame-retardant properties of UPR composites were enhanced. UPR/30DOPO-N passed a UL-94 V-1 rating with a limiting oxygen index (LOI) of 30.8%. The tensile strength of UPR/30DOPO-N increased by 24.4%. On this basis, a small amount of modified HNTs (VHNTs) was added to further improve the flame-retardant properties of the composite. With the introduction of 3 wt% VHNTs, the composite passed the UL-94 V-0 rating. The peak of heat release rate (PHRR) and total heat release (THR) of it decreased by 60.7% and 48.3%, respectively. Moreover, the detailed flame-retarding mechanism of DOPO-N and VHNTs was investigated by thermogravimetric infrared spectroscopy (TG-IR), Raman spectra, and X-ray photoelectron spectroscopy (XPS). It was found that DOPO-N played a role in quenching the flame in the gas phase and cooperated with VHNTs to enhance the barrier effect in the condensed phase.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
·
2020
·Vol. 31
·期 8
·1765-1775
·
IF 2.578
Caixia Li,Chao Ma,Juan Li
Because of good thermal stability, nonflammability and rich structural designability, ionic liquids (ILs) have been used as flame retardants for poly(lactic acid) (PLA). However, as a small molecule, IL has the disadvantages of poor thermal stability and water resistance, and so on. In this paper, an imidazole-type poly(ionic liquid) (PIL) containing a phosphate anion was synthesized using 1-vinylimidazole, triethyl phosphate, and 1,2-divinylbenzene and marked as PDVE[DEP]. The PDVE[DEP] was used to improve the flame retardancy of PLA. The flame retardancy and thermal degradation behaviors of PLA/PDVE[DEP] composites were investigated by the limited oxygen index (LOI), UL-94 vertical burning, cone calorimetry, and thermal gravity analysis, and so on. The results showed that only 1.0 wt% PDVE[DEP] allows PLA to achieve the UL-94 V0 rating and obtain LOI value 25.6 vol%. The PDVE[DEP] improve the flame retardancy of PLA by melting-away mode. In addition, it catalyzes the transesterification of PLA and changes the degradation products.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2018
·
IF 3.468
Siyu Xia,Zhiyong Zhang,Yang Leng,Bin Li,Miaojun Xu
A novel polymeric mono-component intumescent flame retardant poly(piperazine methylphosphonic acid neopentylglycol ester) (PPMPNG) was synthesized from methylphosphonic acid, piperazine and neopentyl glycol. Its chemical structure was detailed characterized by Fourier transform infrared spectroscopy (FTIR), 13 C and 31 P solid-state nuclear magnetic resonance. PPMPNG was incorporated into polyethylene (PE) and the flame retardancy, thermal properties and flame retardant mechanism of materials were investigated. The samples with the thickness of 1.6 mm passed UL-94 V-0 rating during vertical burning tests and the limiting oxygen index was 25.6% when 23 wt% PPMPNG was introduced. The results of thermogravimetric analysis (TGA) showed that the addition of PPMPNG promoted the degradation and carbonization of materials at the beginning and improved the char residue amount and thermal stability of FR-PE at high temperature. Cone calorimeter tests indicated that the peak value of heat release rate was considerably reduced with the incorporation of PPMPNG. The flame retardant mechanism showed PPMPNG exerted isolation effect in condensed phased and quenched active free radical effect in gas phase. The combustion intensity was reduced and the flame was suppressed and even extinguished, thus a high efficiency for PE matrix was achieved.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2024
·
IF 6.3
Liwen Zheng,Jing Zhan,Jiahui Wang,Zhirong Xu,Xiaowei Mu
In recent years, flame-retardant rigid polyurethane foam (RPUF) has once again captured the scholars’ attention due to the growing the growing demands in the field of building energy efficiency. However, the inherent flammability of RPUF is high and the complexities of its flame-retardant mechanisms remain inadequately understood. In this study, a modified biomass material, amino starch phosphate ester was successfully synthesized which was then combined with expandable graphite (EG) and incorporated into RPUF. The research delved into the optimal ratio and minimal flame-retardant additive required to achieve the stringent UL-94 V-0 rating, while also thoroughly investigating the flame retardancy and thermal properties of the composite system. The findings revealed that with just 6 wt.% of flame retardants, the RPUF achieved the UL-94 V-0 rating, with a 41.1 % reduction in peak heat release rate (pHRR) and a 23.7 % decrease in total heat release (THR). Additionally, it diminishes the flame's size and width, leading to quicker extinction, while also lowering the internal combustion temperature of the polyurethane, thereby delaying both preheating and combustion times. The synergistic interaction between amino starch phosphate ester and EG during combustion results in the formation of a dense, continuous char layer, effectively inhibiting the pyrolysis and combustion of RPUF. This study provides a theoretical foundation for the development of efficient flame-retardant systems for RPUF.
研究领域:
材料科学
·
防火安全工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）