无卤阻燃高密度聚乙烯中层状硅酸盐的协效作用

以不同层状硅酸盐部分取代氢氧化铝(ATH)、氢氧化镁(MH)和相容剂AX8900复配协同阻燃高密度聚乙烯(HDPE)复合材料。探讨了不同层状硅酸盐对复合材料极限氧指数、锥形量热参数、热稳定性以及微观结构的影响。结果表明,与未添加层状硅酸盐相比,添加3%~5%的层状硅酸盐能提高极限氧指数和热稳定性,有更低的燃烧热释放速率峰值(p1-HRR、p2-HRR)和热释放总量(THR),也能更好地在基体材料中分散,说明层状硅酸盐在体系中能起到协效阻燃作用。这些层状硅酸盐中,改性的比未改性的协效阻燃作用强,埃洛石(HNTs)和羟基锡酸锌包覆埃洛石(coatedHNTs)比凹凸棒土(AT)和表面改性凹凸棒土(m-AT)能更好地发挥协效阻燃作用。     

新型膨胀阻燃聚丙烯复合材料的协同效应

基于膨胀阻燃与协效阻燃相结合的技术制备了含协效剂的新型膨胀阻燃聚丙烯(PP)复合材料,其中的新型膨胀阻燃剂由硅凝胶包裹聚磷酸铵(OS-MCAPP)和三羟乙基异氰尿酸酯(THEIC)组成,协效剂为多孔磷酸镍(VSB-1)或磷酸镍纳米管(NiPO-NT)。结果表明,当VSB-1和NiPO-NT的添加量(质量分数)分别为4.0%和3.0%时复合材料的极限氧指数可达到最大值34.2,其最大热释放速率比不含协效剂时分别降低了40.7%和38.1%,表现出高效的阻燃协效性。同时,含有VSB-1和NiPO-NT阻燃PP复合材料的热稳定性显著提高,700℃时的残余质量比不含协效剂时分别提高了207%和239%。     

聚酰胺6对聚丙烯/膨胀阻燃体系阻燃性和力学性能的影响

以聚磷酸铵(APP)、季戊四醇(PER)组成的膨胀阻燃剂(IFR)为主阻燃剂，有机蒙脱土(OMMT)为协效阻燃剂，马来酸酐接枝聚烯烃弹性体(POE-g-MAH)为增韧剂，以聚酰胺6(PA6)为聚合物成炭剂，采用熔融共混法制备了PP/PA6/POE-g-MAH/IFR/OMMT阻燃复合材料，并研究了PA6对PP阻燃复合材料阻燃性和力学性能的影响。通过极限氧指数(LOI)、垂直燃烧、热重分析、扫描电子显微镜和力学性能测试等手段对PP阻燃复合材料进行了测试与表征。结果表明：成炭剂PA6的加入，可显著地提高PP阻燃复合材料的阻燃性能，当PA6含量为5%时，PP阻燃复合材料的LOI由原来不含PA6时的25.5%提高到了30.0%,垂直燃烧等级由原来的无等级提高到了UL-94 V-0级，且随着PA6含量的进一步增加，LOI在逐渐增大。但PA6的加入，会使PP阻燃复合材料的力学性能下降。     

聚磷酸铵/次磷酸铝协效阻燃聚丙烯/木粉复合材料

以聚磷酸铵(APP)和次磷酸铝(AHP)为阻燃剂,马来酸酐接枝聚丙烯(MA-g-PP)为界面相容剂,通过熔融共混制备了聚丙烯(PP)/木粉(WF)复合材料。采用UL-94垂直燃烧、氧指数(LOI)、热重分析(TGA)探究了阻燃PP/WF复合材料的阻燃性和热分解过程。实验表明,当APP与AHP质量比为9∶1时,LOI值为28.3%,垂直燃烧UL-94达到V-0级。TGA和DTG测试表明,APP与AHP复配能降低木纤维的分解温度,使复合材料提前成炭,达到阻燃作用;加入APP与AHP的PP/WF复合材料的成炭率提高了141%,其高温稳定性也得到提高。通过SEM观察到,当m(APP)∶m(AHP)=9∶1时,木塑复合材料可形成致密的炭层,具有更好的隔热、隔氧作用,从而提高了阻燃性。结果表明在聚磷酸铵中加入少量的协效剂次磷酸铝可明显提高PP/WF复合材料的阻燃性。     

镁盐晶须增强阻燃LDPE/EVA/ATH复合材料的研究

通过拉伸性能、燃烧性能测试及热失重-差示扫描量热分析(TG-DSC),研究了EVA、镁盐晶须和相容剂的用量对LDPE/EVA/ATH复合体系的影响。结果表明,EVA在复合体系中的最佳用量为m(EVA)∶m(LDPE)=6∶4;镁盐晶须的加入不仅提高了复合材料的拉伸强度和断裂伸长率,而且镁盐晶须与纳米氢氧化铝之间存在协效阻燃作用,提高了复合材料的氧指数;相容剂的加入改善了无机粉体与基体树脂间的相容性,提高了复合材料的力学性能和燃烧性能,相容剂的最佳用量为15 phr。     

分子筛/受阻胺对膨胀阻燃聚丙烯的协同阻燃作用

采用热失重、极限氧指数、锥形量热研究了以受阻胺(NOR116)和分子筛为协效剂,与聚磷酸铵(APP)/季戊四醇(PER)在聚丙烯基体中的热降解行为及协同阻燃性;并用拉曼光谱和扫描电镜分析了残炭的结构和形貌,进一步研究了其协同阻燃机理。结果表明,NOR116/分子筛协效阻燃体系可明显提高极限氧指数并改善燃烧时熔滴缺陷,显著降低热释放速率、烟释放速率;NOR116可有效提高PP的初始分解温度及最大分解速率温度,使膨胀阻燃体系后期的交联成炭及气体释放更加匹配;在燃烧过程中分子筛与膨胀阻燃体系形成了Si-P-Al-C的结构,可有效稳定炭层;拉曼光谱及扫描电镜结果表明,NOR116和分子筛可促进膨胀阻燃体系形成致密且高石墨化程度的炭层,有效阻隔了氧气的进入及热的反馈。     

介孔分子筛和Cr_2O_3协同膨胀阻燃体系对阻燃天然橡胶性能的影响

用介孔分子筛(MCM-41)和Cr_2O_3协同膨胀型阻燃体系(IFR)对天然橡胶(NR)进行阻燃。为研究MCM-41和Cr_2O_3的阻燃协同作用,使用不同组分的两种协效剂协同IFR阻燃天然橡胶。对阻燃体系分别进行氧指数测试、热重分析、锥形量热分析、拉伸测试和残炭扫描分析。研究结果表明:天然橡胶单纯添加IFR时,其力学性能大幅下降,热学性能也没有显著提升。然而随着Cr_2O_3和MCM-41添加量的增加,橡胶基体的拉伸强度和断裂伸长率均有所改善,在IFR添加量为36%(与天然橡胶的质量比)、MCM-41添加量为1%,Cr_2O_3为3%时,IFR-MCM-41-Cr_2O_3复合阻燃剂的阻燃效果最好,热释放速率峰值和热释放总量均明显下降,IFR-MCM-41-Cr_2O_3/NR复合材料燃烧后,炭层发泡均匀且致密,极限氧指数(LOI)可以达到26.5%,垂直燃烧(UL-94)为V-0级。     

RDP与APP/MC/PPO复配膨胀阻燃聚乙烯的研究

采用聚磷酸铵(APP)、三聚氰胺氰脲酸盐(MC)和聚苯醚(PPO)复配制备膨胀阻燃剂(IFR),与阻燃协效剂间苯二酚双(二苯基磷酸酯)(RDP)进行聚乙烯(PE)阻燃。借助氧指数、垂直燃烧测试,探讨IFR与阻燃协效剂RDP间的协效性,研究RDP不同添加量对IFR阻燃复合材料燃烧性能的影响,并对其力学性能进行测试。利用TG,DTG热分析技术对协效性进行验证。结果表明:RDP与IFR具有阻燃协效作用,RDP的协效性主要在热分解的第一阶段发挥作用,可催化APP提前分解,RDP的加入降低了热分解过程的热释放量,促进了多孔泡沫炭层的形成,并显著提高材料的残炭量;当RDP的添加量为5%(质量分数)时,氧指数(LOI)达到最大值31,并通过UL94V-0级。可见RDP与APP/MC/PPO阻燃剂复配可大幅提高PE的抗燃烧性能。     

膨胀型阻燃聚乙烯MWNT复合材料的阻燃性及燃烧性能研究

利用本实验室最近合成的两种新型阻燃剂（SPS和PTEN）与聚磷酸铵㈣及碳纳米管（MWNT）复配，并应用于低密度聚乙烯（LDPE），得到膨胀型阻燃LDPE／MWNT复合材料。通过氧指数（LOI）、垂直燃烧（UL-94）、锥形量热试验（CONE）对膨胀型阻燃LDPE／MWNT复合材料的阻燃性能和燃烧性能进行了研究。结果表明，在该膨胀型阻燃体系中，IFR与MWNT之间存在明显的协效阻燃作用，并且大大降低了低密度聚乙烯的可燃性和热释放速率（H刚时，而且燃烧后的残炭量大大增加。实验的最佳配方可使LDPE的氧指数值达30．6，UL-94达V-0级。     

PP/PVAc-OMMT纳米复合材料及其阻燃材料的燃烧性能

利用锥形量热仪(CONE)在35kW/m2热辐照条件下,并结合极限氧指数(LOI)和UL-94垂直燃烧测试方法对聚丙烯(PP)/聚醋酸乙烯酯(PVAc)-有机蒙脱土(OMMT)纳米复合材料和加入无卤复配阻燃剂制备的PP/PVAc-OMMT/氢氧化镁(MH)/三氧化二锑(AO)纳米复合阻燃材料的热释放速率、烟释放及材料在燃烧时的质量损失行为进行了研究。结果表明,添加10%(质量分数)PVAc-OMMT可以提高PP材料的阻燃性能,燃烧时的热释放速率、质量损失率以及烟释放量减少,且PVAc-OMMT与无卤复配阻燃剂之间可产生阻燃协效作用,使纳米复合阻燃材料的阻燃性能、热稳定性和抑烟性进一步增强。     

含硅阻燃剂与膨胀型阻燃剂的协同阻燃性

采用测量极限氧指数(LOI)和锥形量热仪动态燃烧两种方法评价了含硅阻燃剂(SFR-H)与高聚磷酸铵/三聚氰胺氰尿酸盐(APP/MCA)膨胀阻燃体系在聚乙烯基体中的协同阻燃性,并通过红外光谱(FT-IR)、X射线衍射(WAXD)和扫描电镜(SEM)分析炭层结构和成分来研究其协同阻燃机理。研究表明,SFR-H/APP/MCA协同阻燃体系可明显提高聚乙烯的LOI值和降低燃烧热释放速率,具有较好的协同阻燃性,两者在燃烧过程中一起热氧化分解,形成陶瓷状含硅、硼、磷元素的化合物,对表面膨胀炭层起着增强作用,同时也提高了膨胀炭层的热氧稳定性和阻隔性能,从而提高了阻燃效果。     

纳米氢氧化镁阻燃聚丙烯体系的性能研究

研究了自制的低成本纳米氢氧化镁与市售普通微米氢氧化镁填充的聚丙烯塑料的阻燃性能和力学性能.氧指数测试和拉伸测试的数据表明,在相同填充质量份数下,纳米氢氧化镁填充的聚丙烯体系具有更高的氧指教、拉伸强度和断裂伸长率.对2种填充体系复合材料断口的场发射扫描电镜(FESEM)观察发现,纳米氢氧化镁与聚夸物基体的相容性更好,两者界面间的粘结力更强.因此,填充纳米级氢氧化镁的聚丙烯塑料具有更优异的阻燃性能和力学性能.     

Electron beam irradiated HDPE/EVA/Mg(OH) composites for flame-retardant electric cables

The mechanical properties and flammability of high-density polyethylene (HDPE)/ethylene vinyl acetate (EVA) mixed with various amounts of magnesium hydroxide (Mg(OH)₂) as the filler in composites, irradiated with electron beam at an irradiation dose of 150 kGy, have been studied. It is found that high-energy electron beam irradiation has significant effects on the mechanical properties of the HDPE/EVA/Mg(OH)₂ composites. The tensile strength and elastic modulus increased greater than in the unirradiated ones. Meanwhile, with increasing the content of Mg(OH)₂ in the composites, the limiting oxygen index (LOI) value increased sharply. The microstructure of the caves of the unirradiated HDPE/EVA/Mg(OH)₂ composites show poor interface of composites compared with the irradiated ones, as observed in SEM micrographs.     

Electron beam irradiated HDPE/EVA/Mg(OH)2 composites for flame-retardant electric cables

The mechanical properties and flammability of high-density polyethylene (HDPE)/ethylene vinyl acetate (EVA) mixed with various amounts of magnesium hydroxide (Mg(OH)₂) as the filler in composites, irradiated with electron beam at an irradiation dose of 150 kGy, have been studied. It is found that high-energy electron beam irradiation has significant effects on the mechanical properties of the HDPE/EVA/Mg(OH)₂ composites. The tensile strength and elastic modulus increased greater than in the unirradiated ones. Meanwhile, with increasing the content of Mg(OH)₂ in the composites, the limiting oxygen index (LOI) value increased sharply. The microstructure of the caves of the unirradiated HDPE/EVA/Mg(OH)₂ composites show poor interface of composites compared with the irradiated ones, as observed in SEM micrographs.     

Effect of Amino alcohol functionalized polyethylene as compatibilizer for LDPE/EVA/clay/flame-retardant nanocomposites

The synergistic effect of organo-modified montmorillonite (Nanomer I28E and Cloisite 20A) and metal hydroxides (magnesium hydroxide MH and alumina trihydrate ATH) as flame retardants in LDPE/EVA nanocomposites compatibilized with amino alcohol grafted polyethylene (PEgDMAE) was studied. Morphological characterization of nanocomposites was carried out by means of X-ray diffraction (XRD) and scanning transmission electron microscopy (STEM). Flame-retardant properties of nanocomposites were evaluated by the UL-94 horizontal burning and cone calorimeter tests and limiting oxygen index (LOI). Thermal degradation behavior was analyzed with a Fourier transform infrared coupled with the thermogravimetric analyzer (TG-FTIR). The XRD analysis showed a displacement of the d₀₀₁ plane characteristic peak of clay to lower angles, which indicates an intercalated–exfoliated morphology. From STEM images it was observed a good dispersion of flame retardants (MH and ATH) throughout the polymer matrix which was reflected in flame-retardant properties. TG-FTIR showed a better thermal stability of nanocomposites and the gases evolved during combustion showed an important reduction. Based on thermal stability and thermal degradation results, the flame-retardant mechanism of LDPE/PEgDMAE/EVA/Clay/MH nanocomposites was proposed.     

胶原蛋白/低密度聚乙烯复合材料的制备与性能

为了探讨胶原蛋白（HC）和相容剂马来酸酐接枝低密度聚乙烯（LDPE-g-MAH）对聚合物材料性能产生的影响,以低密度聚乙烯（LDPE）为基体,用共混挤出的方法制备了HC/LDPE复合材料和HC/LDPE-MAH复合材料,并将复合材料注塑成不同规格样条。通过力学性能测试、SEM和热分析等表征方法研究了HC和LDPE-g-MAH含量对HC/LDPE及HC/LDPE-MAH复合材料结构和性能的影响。结果表明：当HC加入量为5wt%时,HC/LDPE复合材料拉伸强度达到最大值15.824 MPa;LDPE-g-MAH的加入可明显改善界面粘结性,提高材料力学性能及热稳定性,当HC含量为20wt%,LDPE-g-MAH含量为4wt%时,HC/LDPE-MAH复合材料的拉伸性能最优。     

β-环糊精-聚磷酸铵对黄麻/聚丙烯复合材料阻燃性能的影响

将黄麻纤维和聚丙烯纤维（PP）通过梳理、铺网和针刺的方式形成黄麻/PP复合材料毡,采用表面撒粉工艺,将阻燃剂β-环糊精（β-CD）、β-CD与聚磷酸铵（APP）复配热压后在黄麻/PP复合材料表面形成阻燃层,采用FTIR、极限氧指数测试仪、水平燃烧测试仪、锥形量热测试仪、热重分析测试仪、SEM及万能试验机等检测黄麻/PP复合材料阻燃性能、力学性能、成炭性能及样品表面微观形貌。结果表明:β-CD与APP复配后在黄麻/PP复合材料表面热压成膜可以显著提高复合材料的阻燃性能和热稳定性。当β-CD-APP复配阻燃剂质量分数为20wt%、β-CD与APP的质量比为1∶2时,黄麻/PP复合材料水平燃烧58 s后自熄,极限氧指数（LOI）值达到26.6%,根据日本JISD 1201—77标准,属于第三难燃等级材料,此时热释放速率和有效燃烧热值最小,700℃时的残炭量增加了11.68%。力学性能测试表明,在黄麻/PP复合材料表面增加阻燃层后,弯曲强度增加而拉伸强度不受影响。      

改性氢氧化镁的制备及在PA66中的阻燃应用

以氯化镁、氢氧化钠、尿素和硬脂酸钠为原料,采用沉淀法制备出改性氢氧化镁(MH)粉末材料。结果表明,制备的MH为无规则的、粒径为30～120nm的,且至少有一维是纳米结构的片状材料。在应用方面,采用熔融挤出法制备了多组不同配方的尼龙66(PA66)复合材料。研究发现,MH单独使用时阻燃效率低,将它与微胶囊红磷(MRP)复配使用后能有效地提高材料的阻燃性能。当x(PA66)∶x(MRP)∶x(MH)=100(phr)∶10(phr)∶8(phr)时,MRP/MH/PA66复合材料的垂直燃烧为V-0级,LOI能达到32%。此外,还探讨了可能的阻燃机理,并通过TG、TG-MS等手段研究了材料的热氧稳定性及热氧分解气态产物。     

Preparation of a Novel Phosphorus–Nitrogen-Containing Flame Retardant by Supramolecular Reaction and its Application in Epoxy Resin

Piperazine hexahydrate (PI) and diethylenetriamine penta(methylene phosphonic acid) (DTPMP) are used to synthesize flame-retardant PI-DTPMP through supramolecular reaction. The incorporation of PI-DTPMP simultaneously improves the mechanical and flame-retardant properties of epoxy resin (EP). With only 5 wt% loading of PI-DTPMP, EP composites show excellent flame retardancy with a limiting oxygen index (LOI) of 36.4% and V-0 rating in the UL-94 test. The cone calorimetric test results demonstrates that the peak heat release rate, total heat release, and total smoke release of EP/5%PI-DTPMP are reduced by 44.9%, 34.7%, and 37.7% compared with that of neat EP, respectively, owing to the formation of compact and insulating char layer during combustion. Moreover, EP/PI-DTPMP composites show enhanced mechanical properties with the improved tensile and impact strength, as well as higher storage modulus, crosslink densities, and glass-transition temperatures in dynamic mechanical analysis.     

Conductive polyolefin–rubber nanocomposites with carbon nanotubes

Polyolefin–rubber composites of differing compositions were formed by melt mixing linear low density polyethylene (LLDPE) and functionalised rubber particles (FRP) through interactions of pre-functionalised polymers in the interface. Following the incorporation of carbon nanotubes to the polymeric composites the nanocomposites filaments were extruded for fused deposition modelling (3D printing). The mechanical properties of the composites (tensile and flexural modulus, yield stress, tensile strength, elongation at break) were compared with respect to how the test specimens were made: compression moulding versus 3D printing. The results showed that increasing the rubber content concentrated the nanotubes in the LLDPE phase forming electrically conductive pathways. The use of maleic anhydride as a compatibilizer improved the mechanical properties of the composites overall. The 3D printed specimens had lower mechanical properties than the compression moulded specimens, though they had the same electrical conductivity.