木粉及聚磷酸铵对PE-HD木塑复合材料阻燃和力学性能的影响

以高密度聚乙烯(PE-HD)为基体,聚磷酸铵(APP)和木粉(WF)为膨胀型阻燃体系,制备了阻燃木塑复合材料(WPC)。通过极限氧指数、垂直燃烧UL 94、锥形量热分析、热失重分析、红外光谱分析、力学性能等对其进行性能表征。结果表明,与纯PE-HD相比,极限氧指数随着WF含量增加而提高,添加40 %WF时极限氧指数提高到30.5 %,UL 94可达V-0等级,热释放速率峰值和总热释放量降低;APP和WF燃烧过程中发生了化学作用,形成了保护炭层,提高了材料的热稳性,材料的拉伸和弯曲强度得到提高。     

Flammability and mechanical properties of wood flour‐filled polypropylene composites

Polypropylene (PP) composites filled with wood flour (WF) were prepared with a twin‐screw extruder and an injection‐molding machine. Three types of ecologically friendly flame retardants (FRs) based on ammonium polyphosphate were used to improve the FR properties of the composites. The flame retardancy of the PP/WF composites was characterized with thermogravimetric analysis (TGA), vertical burn testing (UL94‐V), and limiting oxygen index (LOI) measurements. The TGA data showed that all three types of FRs could enhance the thermal stability of the PP/WF/FR systems at high temperatures and effectively increase the char residue formation. The FRs could effectively reduce the flammability of the PP/WF/FR composites by achieving V‐0 UL94‐V classification. The increased LOI also showed that the flammability of the PP/WF/FR composites was reduced with the addition of FRs. The mechanical property study revealed that, with the incorporation of FRs, the tensile strength and flexural strength were decreased, but the tensile and flexural moduli were increased in all cases. The presence of maleic anhydride grafted polypropylene (MAPP) resulted in an improvement of the filler–matrix bonding between the WF/intumescent FR and PP, and this consequently enhanced the overall mechanical properties of the composites. Morphological studies carried out with scanning electron microscopy revealed clear evidence that the adhesion at the interfacial region was enhanced with the addition of MAPP to the PP/WF/FR composites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

纳米双羟基复合金属氧化物协同聚磷酸铵阻燃尼龙-6/聚丙烯燃烧及热降解行为的研究

将纳米双羟基复合金属氧化物 (LDH)与聚磷酸铵 (APP)在一定范围内复配 ,用于尼龙 6/聚丙烯 (PA 6/PP)共混体系可产生良好的协同阻燃效果。实验表明 ,LDH参与了共混阻燃体系的热分解反应 ,催化了PA 6/PP/APP体系的交联、成炭 ;LDH协同阻燃体系的残炭形态致密、光滑、残炭微孔呈闭合状态。协同阻燃作用的机理与LDH和APP热降解过程中产物间的化学与物理作用有关。     

苯基聚硅氧烷微胶囊化聚磷酸铵的制备及其在PP中阻燃性能研究

采用苯基三甲氧基硅烷为前驱体,通过溶胶凝胶法制备出苯基聚硅氧烷微胶囊化聚磷酸铵（MAPP）。将MAPP作为阻燃剂,季戊四醇（PER）作为成炭剂,制备阻燃聚丙烯（PP）。用傅里叶红外光谱、扫描电子显微镜、能谱仪及热重分析仪对MAPP进行表征。结果表明,聚磷酸铵（APP）被苯基聚硅氧烷成功包覆;较之APP,MAPP的热稳定性和疏水性显著提高;MAPP的阻燃性能优于APP,PP/MAPP/PER复合材料达到V-0级别;阻燃剂及成炭剂的加入对PP的结晶行为有促进作用。     

有机-金属杂化化合物阻燃聚丙烯的研究

将有机-金属杂化三嗪化合物（SCTCFA-ZnO）与聚磷酸铵（APP）复配制备了膨胀型阻燃剂（IFR）,通过极限氧指数测试、垂直燃烧测试、锥形量热分析、热失重分析和扫描电子显微镜分析等表征方法研究了SCTCFA-ZnO/APP的协同作用对PP复合材料阻燃性能的影响。结果表明,APP与SCTCFA-ZnO复配可以有提高PP材料的阻燃性能,当IFR的添加量为25 %（质量分数,下同）,且APP/SCTCFA-ZnO的质量比为2/1时,复合材料的极限氧指数最高,达到31.1 %,达到UL 94 V-0级;IFR可提高复合体系的温热稳定性,阻燃复合材料燃烧后会形成一层致密、连续的炭层,从而起到良好的阻燃效果。     

Study on surface modification and flame retardants properties of ammonium polyphosphate for polypropylene

Microencapsulation ammonium polyphosphate used as flame‐retardant in polypropylene was prepared with hydroxyl silicone oil (HSO) and melamine‐formaldehyde (MF) resin in this article. Fourier transform infrared and energy dispersive spectrometer were used to identify the structure of HSO‐MFAPP. For the HSO‐MFAPP/polypropylene (PP) composites, the flame retardant effect was evaluated by the limiting oxygen index and UL‐94 testing, the compatibility was observed with scanning electron microscope, and the thermal stability was studied by thermogravimetric analysis. The results showed that the microencapsulation of ammonium polyphosphate (APP) with HSO‐MF was prepared by in situ polymerization, and the flame retardant properties and water resistance of the PP/HSO‐MFAPP/pentaerythritol (PER) composites were much better than the ones of the PP/APP/PER composites. Moreover, the compatibility of HSO‐MFAPP with PP was better than that of unmodified APP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Investigation of novel intumescent flame retardant low-density polyethylene based on SiO2@MAPP and double pentaerythritol

To improve the flame-retardant property of low-density polyethylene (LDPE) composites, a novel intumescent flame retardant (IFR) consisting of ammonium polyphosphate (APP) covered by silicon dioxide and 3-(Methylacryloxyl) propyltrimethoxy silane (KH-570) (SiO₂@MAPP) and double pentaerythritol (DPER) was synthesized. Various methods were applied to structural characterization and property investigations of different samples. The results indicated that the solubility of APP decreased after coating with silicon dioxide (SiO₂) and KH-570. The flame retardancy of LDPE composites was improved with addition of IFR containing SiO₂@MAPP/DPER. With 30 wt% addition of IFR containing SiO₂@MAPP /DPER, the limiting oxygen index reached 26.8% and the tensile strength was 3.30 MPa. The tensile strength was 7.14% higher than that of 30 wt% IFR without SiO₂@MAPP. The smoke density test showed that the flue gas emission was obviously improved. The addition of SiO₂@MAPP effectively increased the residual carbon content of composites and thermal stability of the composites.     

Study on flame retardance of co‐microencapsulated ammonium polyphosphate and dipentaerythritol in polypropylene

Co‐microencapsulated ammonium polyphosphate and dipentaerythritol [M(A&D)] was prepared using a melamine‐formaldehyde (MF) resin by in situ polymerization method, and characterized by XPS. The co‐microencapsulation of ammonium polyphosphate and dipentaerythritol (DPER) leads to a great improvement in water solubility of the additives. The flame retardant effect of M(A&D) in polypropylene (PP) is evaluated using limiting oxygen index (LOI) and UL 94 test, and the water resistance of the PP/M(A&D) composites is also studied. The flame retardant properties and water resistance of the PP/M(A&D) composites are much better than the ones of the PP/APP/DPER composites. Moreover, the thermal stability of the PP/M(A&D) composites is improved compared with the PP/APP/DPER composites. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

Component ratio effects of hyperbranched triazine compound and ammonium polyphosphate in flame‐retardant polypropylene composites

A hyperbranched derivative of triazine group (EA) was synthesized by elimination reaction between ethylenediamine and cyanuric chloride. The different‐mass‐ratio EA and ammonium polyphosphate (APP) were mixed and blended with polypropylene (PP) in a constant amount (25%) to prepare a series of EA/APP/PP composites. The component ratio effect of EA/APP on the flame‐retardant property of the EA/APP/PP composites was investigated using the limiting oxygen index (LOI), vertical burning (UL‐94), and cone calorimetry tests. Results indicated that the EA/APP/PP (7.50/17.50/75.00) composite with the appropriate EA/APP mass ratio had the highest LOI, UL94 V‐0 rating, lowest heat release rate, and highest residue yield. These results implied that the appropriate EA/APP mass ratio formed a better intumescent flame‐retardant system and adequately exerted their synergistic effects. Furthermore, average effective combustion heat values revealed that EA/APP flame retardant possessed the gaseous‐phase flame‐retardant effect on PP. Residues of the EA/APP/PP composites were also investigated by scanning electron microscopy, Fourier‐transform infrared, and X‐ray photoelectron spectroscopy. Results demonstrated that the appropriate EA/APP mass ratio can fully interact and lock more chemical constituents containing carbon and nitrogen in the residue, thereby resulting in the formation of a dense, compact, and intumescent char layer. This char layer exerted a condensed‐phase flame‐retardant effect on EA/APP/PP composites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41006.     

Properties of flat‐pressed wood plastic composites containing fire retardants

This study investigated physical, mechanical, and fire properties of the flat‐pressed wood plastic composites (WPCs) incorporated with various fire retardants (FRs) [5 or 15% by weight (wt)] at 50 wt % of the wood flour (WF). The WPC panels were made from dry‐blended WF, polypropylene (PP) with maleic anhydride‐grafted PP (2 wt %), and FR powder formulations using a conventional flat‐pressing process under laboratory conditions. The water resistance and strength values of the WPC panels were negatively affected by increasing the FR content as compared to the WPC panels without FR. The WPC panels incorporated with zinc borate (ZB) gave an overall best performance in both water resistance and strength values followed by the panels containing magnesium hydroxide (MH) and ammonium polyphosphate (APP). For these three FR's, the best fire resistance as measured in the cone calorimeter was obtained with the 15 wt % APP treatment and then followed by 15 wt % ZB, or 15 wt % MH formulations. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

木粉填充HDPE/PVC复合材料的热稳定性及流变行为

以聚磷酸铵(APP)和Al(OH)3为阻燃剂,通过熔融挤出制备了具有阻燃性能的高密度聚乙烯/聚氯乙烯(HDPE/PVC)基木塑复合材料,研究了PVC对木塑复合材料热稳定性及流变行为的影响。热失重分析结果表明:APP和PVC均可促进木粉成炭,同时提高了HDPE的热稳定性;流变测试结果表明:PVC与木粉的相容性较HDPE要好,并能促进木粉在体系中均匀分散,改善木塑复合材料体系的加工流动性;锥形量热测试结果表明:PVC脱氯、Al(OH)3热分解均吸收大量热量,可降低复合材料的热释放速率与热释放总量。     

Synergistic effect of a novel charring agent with ammonium polyphosphate on flame retardancy and thermal degradation of acrylonitrile‐butadiene‐styrene copolymer

A novel charring agent poly(1,3‐propylene terephthalamide) (PPTA) was synthesized and characterized by Fourier transform infrared spectroscopy and ¹H nuclear magnetic resonance. This novel charring agent combined with ammonium polyphosphate (APP) was adopted as an intumescent flame retardant (IFR) to impart flame retardance and dripping resistance to acrylonitrile‐butadiene‐styrene copolymer (ABS). Flammability and thermal behaviors of the treated ABS were investigated by limiting oxygen index, vertical burning test and thermogravimetric analysis. The results showed that the IFR with the novel charring agent had both excellent flame retardant and anti‐dripping abilities for ABS. The thermogravimetric analysis curves indicated that there was a synergistic effect between PPTA and APP, which greatly promoted the char formation of IFR‐ABS composites. Meanwhile, the thermal degradation mechanism of PPTA and APP/PPTA was characterized using thermogravimetric analysis/infrared spectrometry. The results demonstrated that APP changed the thermal degradation behavior of PPTA and reacted with PPTA to form a crosslinked structure. Additionally, the structure and morphology of char residues were studied by Fourier transform infrared spectroscopy and scanning electron microscopy. Copyright © 2011 Society of Chemical Industry     

Microencapsulation of APP‐I and influence of microencapsulated APP‐I on microstructure and flame retardancy of PP/APP‐I/PER composites

In this article, the microencapsulated ammonium polyphosphate crystalline with form I (APP‐I) coated with melamine‐formaldehyde (MF) was prepared by in situ polymerization. Results of Fourier transform infrared spectra (FTIR), thermogravimetry (TG) energy dispersive spectroscopy (EDS), and scanning electron microscopy (SEM) demonstrate that APP‐I is successfully microencapsulated with MF. Compared with APP‐I, the microencapsulated APP‐I with MF (MFAPP‐I) is of much smaller spheroidal particle size and lower solubility in water. In this study, the polypropylene (PP)/APP‐I/penpaerythritol (PER) and PP/MFAPP‐I/PER composites are prepared, and flame retardancy, thermal stability, and microstructure of corresponding composites are carefully investigated by limiting oxygen index (LOI), UL‐94 testing, TG, EDS, and SEM. Experimental results show that PP/MFAPP‐I/PER composites have advantages over PP/APP‐I/PER composites in terms of flame retardant properties and water resistance. Results of TG, SEM, and EDS show that the microencapsulated APP‐I with MF resin is conducive to increase the amount of residual yield and improve thermal stability of PP/MFAPP‐I/PER composites and the compatibility and dispersion of MFAPP‐I. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis of novel triazine charring agent and its effect in intumescent flame‐retardant polypropylene

A novel charring agent (CNCA‐DA) containing triazine and benzene ring, using cyanuric chloride, aniline, and ethylenediamine as raw materials, was synthesized and characterized. The effects of CNCA‐DA on flame retardancy, thermal degradation, and flammability properties of polypropylene (PP) were investigated by limited oxygen index (LOI), vertical burning test (UL‐94), thermogravimetric analysis (TGA), and cone calorimeter test (CCT). The TGA results showed that CNCA‐DA had a good char forming ability, and a high initial temperature of thermal degradation; the char residue of CNCA‐DA reached 18.5% at 800°C; Ammonium polyphosphate (APP) could improve the char residue of APP/CNCA‐DA system, the char residue reached 31.6% at 800°C. The results from LOI and UL‐94 showed that the intumescent flame retardant (IFR) containing CNCA‐DA and APP was very effective in flame retardancy of PP. When the mass ratio of APP and CNCA‐DA was 2 : 1, and the IFR loading was 30%, the IFR showed the best effect; the LOI value reached 35.6%. It was also found that when the IFR loading was only 20%, the flame retardancy of PP/IFR can still pass V‐0 rating in UL‐94 tests, and its LOI value reached 27.1%. The CCT results demonstrated that IFR could clearly change the decomposition behavior of PP and form a char layer on the surface of the composites, consequently resulting in efficient reduction of the flammability parameters, such as heat release rate (HRR), total heat release (THR), smoke production rate (SPR), total smoke production (TSP), and mass loss (ML). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Thermal degradation and combustion behavior of intumescent flame‐retardant polypropylene with novel phosphorus‐based flame retardants

The objective of this study was to develop an environmentally friendly fire‐retardant polypropylene (PP) with significantly improved fire‐retardancy performance with a novel flame‐retardant (FR) system. The system was composed of ammonium polyphosphate (APP), melamine (MEL), and novel phosphorus‐based FRs. Because of the synergistic FR effects among the three FRs, the FR PP composites achieved a V‐0 classification, and the limiting oxygen index reached as high as 36.5%. In the cone calorimeter test, both the peak heat‐release rate (pHRR) and total heat release (THR) of the FR PP composites were remarkably reduced by the incorporation of the novel FR system. The FR mechanism of the MEL–APP–FR–PP composites was investigated through thermogravimetric analysis and char residue characterization, and the results reveal that the addition of MEL–APP–FRs promoted the formation of stable intumescent char layers. This led to the reduction of pHRR and THR and resulted in the improvement of the fire retardancy. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45962.     

Synergistic effects of tetrabutyl titanate on intumescent flame‐retarded polypropylene

The synergistic mechanism of tetrabutyl titanate (TBT) in the intumescent flame‐retardant polypropylene (PP) composites was investigated in this work. The intumescent flame‐retardant was composed of pentaerythritol (PER) as a carbonizing agent ammonium polyphosphate (APP) as a dehydrating agent and blowing agent. Five different concentrations (1, 1.25, 1.5, 1.75, 2 wt %) of TBT were incorporated into flame retardant formulation to investigate the synergistic mechanism. The thermal degradation and flammability of composites were characterized by thermogravimetric analysis (TGA), limiting oxygen index (LOI), and UL‐94 tests. The morphology and chemical structure of char layer was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and energy dispersive spectrometer (EDS). The results showed that LOI was increased from 27.8 to 32.5%, with the increase of TBT content from 0 to 1.5 wt %. Results from SEM, and FTIR demonstrated that TBT could react with APP and PER to form the stable char layer. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4255–4263, 2013     

Using PA6 as a charring agent in intumescent polypropylene formulations based on carboxylated polypropylene compatibilizer and nano‐montmorillonite synergistic agent

The intumescent fire retardant polypropylene (IFP/PP) filled with ammonium polyphosphate (APP), melamine (M), and PA6 (charring agent) is discussed. Intumescing degree (ID) and the char yield were determined. Only when the three main components of IFR coexist at appropriate proportions, it has optimal ID and higher char yield. The appropriate proportion is PA6 : APP : M = 10 : 10 : 5. A new compatibilizer, carboxylated polypropylene (EPP), was added to PP/PA‐6 blend. Flow tests indicated that the apparent viscosity increased with the addition of EPP, thermal characterization suggested that EPP has reacted with PA6, PA6‐g‐EPP cocrystallized with PA6, and EPP‐g‐PA6 cocrystallized with PP; SEM micrographs illustrated that the presence of EPP improved the compatibility of PP and PA6. All the investigations showed that EPP was an excellent compatibilizer, and it was a true coupling agent for PP/PA6 blends. Using PA6 as a charring agent resulted in the IFR/PP dripping, which deteriorated the flammability properties. The addition of nano‐montmorillonite (nano‐MMT) as a synergistic agent of IFR enabled to overcome the shortcoming. The tensile test testified that the addition of nano‐MMT enhanced the mechanical strength by 44.3%. SEM showed that nano‐MMT improved the compatibility of the composites. It was concluded that the intumescent system with nano‐MMT was an effective flame retardant in improving combustion properties of polypropylene. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 739–746, 2006     

Expandable graphite's versatility and synergy with carbon black and ammonium polyphosphate in improving antistatic and fire‐retardant properties of wood flour/polypropylene composites

This study investigated the antistatic and fire‐retardant properties of wood flour/polypropylene composites consisting of carbon black (CB), ammonium polyphosphate (APP), and expandable graphite (EG) through resistance meter measurement, cone calorimetry (CONE), thermogravimetric analysis (TGA), and scanning electron microscopy. Antistatic property testing confirmed a positive effect between CB and EG on discharging electrostatic charge. Electrostatic charge was thus considered able to be conducted between CB particles through EG, which acted as a bridge in the CB/EG ‐ treated composites. The results of CONE tests showed that EG significantly reduced the smoke release of the wood plastic composites (WPCs), including total smoke release (TSR), average specific extinction area (SEA), and production of carbon monoxide. During the WPCs burning process, a compound of EG and APP showed synergistic effects which decreased heat release and fixed the residual char. TGA results demonstrated that combining EG with APP, as opposed to using EG only, effectively increased the residual mass and decreases the initial thermal decomposition temperature of the WPCs. Addition of APP caused the wood flour char by catalyzing at a lower temperature, moreover, EG and APP displayed good synergistic effects on fire inhibition and smoke suppression. POLYM. COMPOS., 38:767–773, 2017. © 2015 Society of Plastics Engineers     

Influence of polyamide 6 as a charring agent on the flame retardancy,thermal, and mechanical properties of polypropylene composites

In this work, polyamide 6 (PA6) as a charring agent has been used in combination with thermoplastic polyurethane (TPU)‐microencapsulated ammonium polyphosphate (MTAPP) forming intumescent flame retardants (IFRs) which applies in polypropylene (PP). The effects of the IFRs on the flame retardancy, morphology of char layers, water resistance, thermal properties and mechanical properties of flame‐retardant PP composites are investigated by limiting oxygen index (LOI), UL‐94 test, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and mechanical properties test. The results show that the PP/MTAPP/PA6 composites exhibit much better flame‐retardant performances than the PP/MTAPP composites. The higher LOI values and UL‐94 V‐2 of the PP/MTAPP composites with suitable amount of PA6 are obtained, which is attributed to the thick and compact char layer structure evidenced by SEM. The results from TGA and DSC demonstrate that the introduction of PA6 into PP/MTAPP composites has a great effect on the thermal stability and crystallization behaviors of the composites. Furthermore, the mechanical properties of PP/MTAPP/PA6 composites are also improved greatly due to the presence of PA6 as a charring agent. POLYM. ENG. SCI., 55:1355–1360, 2015. © 2015 Society of Plastics Engineers     

Three in one: β‐cyclodextrin,nanohydroxyapatite, and a nitrogen‐rich polymer integrated into a new flame retardant for poly (lactic acid)

A new halogen‐free flame retardant was developed by integrating β‐cyclodextrin, triazin ring, and nanohydroxyapatite (BSDH) into a hybrid system. A β‐cyclodextrin was grafted to a commercially available SABO®STAB UV94 via an aromatic deanhydrate. The BSDH was prepared in situ in the presence of β‐cyclodextrin‐grafted nitrogen‐rich precursor. The resulting hybrid was applied as a flame retardant for poly(lactic acid) (PLA) and compared for performance with ammonium polyphosphate (APP). PLA composites containing BSDH and APP, individually or simultaneously, were examined for thermal degradation and flammability by TGA, cone calorimeter, and pyrolysis‐combustion flow calorimetry. TGA results confirmed enhancement of thermal stability of PLA with assistance of BSDH compared to APP. The gases evolved during thermal degradation were assessed by a thermogravimetric analysis and Fourier infrared spectroscopy device. APP revealed catalytic effect to initiate PLA degradation, while BSDH continued to release some gases at elevated temperatures. The flame retardancy of PLA/APP/BSDH blend containing only 10 wt.% of additives was significantly improved. In cone calorimetric tests, a significant fall in peak of heat release rate was observed for this sample, 49% more than that of neat PLA, which was indicative of more gas and condensed phase reflected in more char residue. The corresponding PLA/APP sample, however, showed 17% improvement, as compared to neat PLA. Also, total heat release rate of PLA/APP/BSDH was 45 MJ.m^?2, whereas those of PLA and PLA/APP were 89 and 65 MJ.m^?2, respectively. BSDH and APP showed a synergistic effect on improving the flame retardancy of PLA composites.