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     

Microencapsulation of ammonium polyphosphate: Preparation,characterization, and its flame retardance in polypropylene

Microencapsulated ammonium polyphosphate (MCAPP) with a melamine–formaldehyde (MF) resin coating layer was prepared by in situ polymerization. MCAPP was characterized by Fourier transform infrared, X‐ray photoelectron spectroscopy, and so on. The results show that the microencapsulation with MF resin leads to a decrease in the particles' size and water absorption. The flame retardant action and mechanism of MCAPP and ammonium polyphosphate (APP) in polypropylene are studied using limiting oxygen index (LOI) and UL 94 test, and their thermal stability is evaluated by thermogravimetric analysis. The LOI value of the PP/MCAPP composite at 30 wt% loading is 30.5%, whereas the corresponding value of the PP/APP composite is only 20%. Moreover, the LOI values of the PP/MCAPP/PER composites are higher than the ones of the PP/APP/PER composites. In the UL 94 test, the PP/MCAPP/PER composites with suitable ratios of MCAPP to PER can reach the V‐0 rating, and the best rating of the PP/APP/PER composites is V‐1. V‐1. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Synergistic effects of hydroxy silicone oil on intumescent flame retardant polypropylene system

The effects of hydroxy silicone oil as a synergistic agent on the flame retardancy of intumescent flame retardant polypropylene composites (IFR-PP) were studied, and the IFR system mainly consisted of the ammonium polyphosphate (APP), melamine (MEL) and pentaerythritol (PER). The UL 94 rating, thermogravimetric analysis (TGA), cone calorimeter (CONE) and digital photograph were used to evaluate the synergistic effects of hydroxy silicone oil (HSO). It has been found that the PP composite containing only APP, MEL and PER does not show good flame retardancy at 30% additive level. The cone calorimeter results show that the heat release rate, mass loss rate, mass, total heat release, carbon monoxide and carbon dioxide of PP/APP/MEL/PER/HSO composites decrease in comparison with the PP/APP/MEL/PER composite. The digital photographs demonstrated that HSO could promote to form the homogenous and compact intumescent char layer. Thus, a suitable amount of HSO plays a synergistic effect in the flame retardancy.     

Vinyl polysiloxane microencapsulated ammonium polyphosphate and its application in flame retardant polypropylene

Vinyl polysiloxane microencapsulated ammonium polyphosphate (MAPP) was prepared by a sol-gel method using vinyltrimethoxysilane as a precursor to improve its thermal stability and hydrophobicity. The MAPP was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and thermogravimetric analyzer (TGA). The results showed that ammonium polyphosphate (APP) was successfully coated with vinyl polysiloxane. MAPP and pentaerythritol (PER) were used together to improve the flame retardancy of polypropylene (PP). The flame retardant properties of PP composites were investigated by limiting oxygen index (LOI), UL-94 test, TGA and SEM. When the MAPP was added as a flame retardant, with PER as a char forming agent, the LOI of PP/MAPP/PER composites was 33.1%, and it reached the UL-94 V-0 level. The results also demonstrated that the flame retardant properties of PP/MAPP/PER composites were better than those of PP/APP/PER composites at the same loading. Moreover, the addition of flame retardant and carbon forming agent could promote the crystallization behavior of PP.     

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。     

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     

三聚氰胺-甲醛树脂微胶囊包覆聚磷酸铵阻燃PP的性能

通过原位聚合法制备三聚氰胺-甲醛树脂(MF)微胶囊包覆聚磷酸铵(APP)粒子,研究了APP粒径对微胶囊化APP(MCAPP)结构与性能的影响。将两种MCAPP(APP平均粒径分别为5,15μm)添加至聚丙烯(PP)基体中,研究了PP/MCAPP阻燃材料的性能。结果表明:不同粒径的APP均能成功被MF包覆,且包覆后的APP粒子的水溶性均大幅下降。PP/MCAPP阻燃材料的耐渗析性和极限氧指数均得到一定程度的提高。粒径小的APP有利于MF的包覆,包覆结构层更完整。MF和APP有很好的协同作用,在APP包覆不完全的情况下,能更有效地发挥两者的相互作用,提高PP复合材料的阻燃性。     

凹凸棒对聚丙烯/聚磷酸铵/季戊四醇复合材料阻燃性能及力学性能的影响

以聚丙烯为基体,多聚磷酸铵(APP)/季戊四醇(PER)/凹凸棒(ATP)为复配阻燃剂(其中APP/PER质量比为3:1),通过熔融共混的方法制备聚丙烯复合材料.采用透射电子显微镜(TEM)考察原土ATP的微观形貌和PP/APP/PER/ATP复合材料的阻燃性能及力学性能.实验结果表明:ATP与APP/PER对PP有协同阻燃作用.当ATP质量含量为2%,复配阻燃剂APP/PER/ATP总量为26%时,PP/APP/PER/ATP复合材料的氧指数为32%,拉伸强度比纯PP提高4.3%,冲击强度比纯PP也提高15.2%.     

Synthesis of a novel intumescent flame retardant and its flame retardancy in polypropylene

Microencapsulated ammonium polyphosphate (GMFAPP) is prepared by in situ polymerization method with a shell of poly(ethylene glycol) modified melamine-formaldehyde resin. Due to the presence of shell, GMFAPP shows less size, higher water resistance and flame retardancy in polypropylene (PP) compared with ammonium polyphosphate (APP). The flame retardant action of GMFAPP and APP in PP are studied using LOI, UL-94 and cone calorimeter, and their thermal stability is evaluated by thermogravimetric apparatus. The limiting oxygen index (LOI) value of the PP/GMFAPP at the same loading is higher than the value of PP/APP. UL-94 ratings of PP/GMFAPP can reach V-0 at 30 wt% loading. The water resistant properties of the PP composites are studied, and the results of the composites containing with APP and GMFAPP are compared. The cone results put forward that GMFAPP is an effective flame retardant in PP compared with APP. Moreover, the thermal oxidative behavior of GMFAPP is evaluated by dynamic FTIR to study its flame retardant mechanism in PP.     

新型阻燃技术在聚丙烯中的应用

将一种膨胀阻燃促进剂ＺＥＯ加入ＡＰＰ（聚磷酸铵）／ＰＥＲ（季戊四醇）膨胀阻燃剂中,用于阻燃ＰＰ（聚丙烯）。这种新型阻燃技术大幅度提高了ＡＰＰ／ＰＥＰ阻燃ＰＰ的效果,极限氧指数（ＬＯＩ）由２７．５上升到４２．０;垂直燃烧试验（ＵＬ－９４）达到Ｖ－０级;锥形量热仪给出的热释放和烟释放等参数也显著下降。本文还采用热重分析仪（ＴＧＡ）、自制热膨胀绝缘测量仪（ＴＦＩＴ）等手段研究了ＺＥＯ促进阻燃效果的机理。     

Synergistic effect of organo‐montmorillonite on intumescent flame retardant ethylene‐octene copolymer

Nanocomposite of thermoplastic elastomer ethylene‐octene copolymer/maleated ethylene‐octene (POE/POE‐g‐MAH) with organo‐montmorillonite (OMMT, 11 wt %) as masterbatch have been obtained by melt blending and it has been characterized by transmission electron microscopy (TEM). Flame retardant POE/POE‐g‐MAH/OMMT/ammonium polyphosphate‐pentaerythritol (APP‐PER) (an intumescent flame retardant with 75 wt % ammonium polyphosphate and 25 wt % pentaerythritol) composites were prepared by using melting processing to study their structures, flame‐retardancy, thermal, and mechanical properties. TEM showed exfoliated structures throughout POE/POE‐g‐MAH/OMMT masterbatch and POE/POE‐g‐MAH/OMMT/APP‐PER nanocomposites. Synergistic effect was observed between OMMT and APP‐PER resulting in significant improvements on thermal stability, flame‐retardancy and mechanical properties in the POE/POE‐g‐MAH/OMMT/APP‐PER nanocomposites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Influence of ammonium polyphosphate modified with 3‐(methylacryloxyl) propyltrimethoxy silane on mechanical and thermal properties of wood flour–polypropylene composites

In this article, the influence of ammonium polyphosphate (APP) and ammonium polyphosphate modified with 3‐(Methylacryloxyl) propyltrimethoxy silane (M‐APP) on mechanical properties, flame retardancy, and thermal degradation of wood flour–polypropylene composites (WF/PP composites) have been investigated. Polypropylene grafted with m‐isopropenyl‐α,α‐dimethylbenzyl‐isocyanate (m‐TMI‐g‐PP) was used to improve the adhesion of WF/PP composites. APP and M‐APP were used as flame retardants. The experimental results demonstrated that addition of M‐APP obviously enhanced mechanical properties of WF/PP composites. According to cone calorimetry results, M‐APP is also an effective flame retardant for WF/PP composites, compared to that of APP. It was also found that M‐APP decreased the 1% weight loss temperature and increased char residue. The thermal degradation of wood flour based upon the first peak temperature of wood decreased from 329.3 to 322.9°C and the thermal degradation of PP based upon the second peak temperature of PP improve from 518.0 to 519.6°C, when M‐APP was added to the WF/PP composites. From SEM results the char layer of the 25% M‐APP systems is much more intumescent than that of the 25% APP systems, indicating that 3‐(Methylacryloxyl) propyltrimethoxy silane can improve the char‐forming ability of WF/PP composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

膨胀阻燃三元乙丙橡胶/聚丙烯热塑性硫化胶的性能

分析了膨胀型阻燃剂聚磷酸铵(APP)、季戊四醇(PER)的加入方式对三元乙丙橡胶(EPDM)/聚丙烯(PP)体系硫化特性的影响,研究了加入不同膨胀型阻燃剂及协效剂硼酸锌(ZB)、有机蒙脱土(OMMT)对动态硫化EPDM/PP热塑性硫化胶(EPDM/PPTPV)性能的影响。结果表明,在动态硫化前加入APP或PER时,EPDM/PP体系不能进行硫化;当APP的加入量为30份时,EPDM/PPTPV的综合力学性能较佳;在EPDM/PPTPV中同时加入APP、PER、三聚氰胺(MEL)时,随着三者加入量的增加,体系的阻燃性能增强,但拉伸强度明显降低,三者的最佳用量为30份APP、10份PER、10份MEL,此时体系的黏度与纯EPDM/PPTPV相当;加入ZB或OMMT时,EPDM/PPTPV的拉伸强度降低,且加入OMMT体系的阻燃效果优于加入ZB体系;加入OMMT时,在低剪切速率下,体系的黏度减小;在高剪切速率下,体系的黏度增大;加入ZB时,在低剪切速率下,体系的黏度与未加ZB体系相当;在高剪切速率下,体系的黏度增大。     

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.     

Effect of intumescent compositions on flammable properties of ethylene vinyl acetate and polypropylene

An intumescent flame retardant (IFR) system was prepared by 2 ways. Firstly, bis(2,6,7‐trioxa‐1‐phosphabicyclo[2,2,2]octane‐1‐oxa‐4‐hydroxymethyl) phosphonate methyl (bis‐PM) was synthesized and characterized by ¹H nuclear magnetic resonance (NMR), ³¹P NMR, and Fourier transform infrared spectroscopies. This carbonization agent was mixed with melamine (ME), ammonium polyphosphate (APP), and pentaerythritol (PER) to constitute an IFR system. Secondly, an IFR system by reaction was prepared by reaction, and the presence of compositions in product was confirmed by ¹H NMR and Fourier transform infrared. Both of systems enhanced the flammable retardation of ethylene vinyl acetate (EVA) and polypropylene (PP). Flammability and thermal behaviors of IFR‐EVA and IFR‐PP were investigated by vertical burning test (UL‐94 V) and thermogravimetric analysis. Results indicated that the IFR systems performed excellent flame retardancy and antidripping ability for PP. At 30 wt% loading, the optimum flame retardant formulations that are bis‐PM/ME: 4/1, bis‐PM/ME/PER: 3/1/1, APP/ME/PER: 3/1/1, and bis‐PM/ME/PER/APP: 1.5/1.5/1/1 give UL‐94 V‐0 rating. However, V‐0 rating results were only obtained for EVA when systems contain bis‐PM/ME: 4/1 and bis‐PM/ME/PER: 3/1/1. The char yield from decomposition of the IFR‐EVA and IFR‐PP has effects on the flame retardancy and antidripping behaviors of EVA and PP.     

Synthesis of amino trimethylene phosphonic acid melamine salt and its application in flame‐retarded polypropylene

Amino trimethylene phosphonic acid melamine salt (MATMP) was synthesized and used as acid source and blowing agent in intumescent flame‐retarded polypropylene (PP); its compositions were characterized by Fourier transform infrared spectroscopy and X‐ray powder diffraction. An intumescent flame retardant (IFR) system composed of MATMP, pentaerythritol (PER), and PP was tested by limiting oxygen index (LOI), UL‐94, cone calorimeter tests, and thermogravimetric analysis and compared with an ammonium polyphosphate (APP)/PER system. The results showed that MATMP had better water resistance than APP, the LOI value of PP/MATMP/PER composite can reach 30.3%, and a UL‐94 V‐0 rating can be reached at 25 wt % IFR loading. The amount of residual char of IFR MATMP/PER was 20.3 and 9.5 wt % at 400 and 600 °C, respectively. A thermooxidative degradation route and a possible flame‐retardant mechanism of IFR were proposed according to the analysis of evolved gases and residual chars. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46274.     

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。     

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     

Studies of polypropylene–intumescent flame‐retardant composites based on etched polypropylene as a coupling agent

The ammonium polyphosphate (APP)–pentaerythritol (PT)–melamine (M) system was selected as an intumescent flame retardant (IFR). The influence of dichromic acid–etched polypropylene (EPP) on the properties and compatibility of IFR/polypropylene (PP) composites was studied. The results obtained from mechanical tests and SEM showed that EPP was a true coupling agent for IFR/PP blends, but without changing the necessary flame retardancy. The cocrystallization between bulk PP and PP segments of EPP was confirmed by WAXD analysis. Flow tests showed that the flow behavior of composites in the melt is that of a pseudoplastic liquid, which is significant for EPP's effect on the rheological behavior of IFR/PP composite. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1388–1391, 2004     

Preparation and characterization of cyclodextrin microencapsulated ammonium polyphosphate and its application in flame retardant polypropylene

A novel microencapsulated ammonium polyphosphate (MAPP) with shell of crosslinked β-cyclodextrin (HDI-CD) was prepared. The HDI-CD shell had a fibrous structure and covered with good completeness on the APP core, and a solid chemical bonding was found between the APP core and HDI-CD shell. The microcapsules were more hydrophobic than the pristine APP. When compounded within polypropylene (PP), the MAPP exhibited good compatibility and dispersibility. The combustion testing results showed that the novel all-in-one intumescent flame retardant had efficient flame retardancy for PP materials.