Preparation of Co⁃microencapsulated Ammonium Polyphosphate/Aluminum Hypophosphite and Its Application in Flame⁃retardant Polypropylene

doi:10.19491/j.issn.1001-9278.2020.11.001

Abstract

Abstract:

The co-microencapsulated ammonium polyphosphate/aluminum hypophosphite ［M（A-A）］ was prepared as a flame retardant using melamine–formaldehyde （MF） resin as wall material. The encapsulating effect of MF was examined by Fourier-transform infrared spectroscopy， scanning electron microscopy and water solubility test. The flame?retardant effect of M（A-A） on polypropylene （PP） was investigated by vertical combustion test， limit oxygen index and cone calorimeter. The mechanical properties of flame?retardant PP were characterized by impact and tensile tests. The results indicated that ammonium polyphosphate/aluminum hypophosphite was successfully encapsulated by MF resin， leading to an effective improvement of water resistance. M（A-A） exhibited better flame retarding efficiency than the pristine flame retardant at the same loading in PP. The heat release rate and total heat release of flame?retardant PP were reduced significantly， and its impact strength increased at first and then tended to decrease with the increase of M（A-A） content. The microencapsulation of flame retardants seemed to reduce the deterioration in tensile properties of PP.

Key words: co-microencapsulation, aluminum hypophosphate, ammonium polyphosphate, polypropylene, flame retardant

CLC Number:

TQ323.3

LI Borui, XIAO Shujuan , WU Shuanghan , YU Shouwu . Preparation of Co⁃microencapsulated Ammonium Polyphosphate/Aluminum Hypophosphite and Its Application in Flame⁃retardant Polypropylene[J]. China Plastics, 2020, 34(11): 1-5.

Figures/Tables 8

Fig.1. FTIR curves of A?A, M(A?A) and MF resin

Fig.2. Optical micrograph of A?A and M(A?A)

Fig.3. SEM of A?A and M(A?A)

样品名称	PP含量/%	A?A含量/%	M(A?A)含量/%	极限氧指数 /%	UL 94测试
样品名称	PP含量/%	A?A含量/%	M(A?A)含量/%	极限氧指数 /%	是否熔滴	阻燃级别
PP?0	100	0	0	19.0	是	无级别
PP?1	70	30	0	26.3	是	无级别
PP?2	80	0	20	25.6	否	V?1
PP?3	70	0	30	28.9	否	V?0

Tab.1. LOI value and UL?94 rating of PP and PP/IFR composites.

Fig.4. RHRR curves of the flame retardant composites

Fig.5. HTHR curves of the flame retardant composites

Fig.6. Impact strength of the flame retardant composites

Fig.7. Tensile strength of the flame retardant composites

References 13

1	WANG X J，WANG Z B，LI J. Effects of a Semi‐Bio‐Based Triazine Derivative on Intumescent Flame‐Retardant Polypropylene［J］. Polymers for Advanced Technologies， 2019， 30（5）： 1 259⁃1 268.
2	ZHANG Y，HE S L，WU J N， et al. Application of Waste Silicon Rubber Composite Treated by N₂ Plasma in the Flame‐Retardant Polypropylene［J］. Journal of Applied Polymer Science， 2019， 136（45）： 48187.
3	WANG X B，BI B，LIU J W， et al. Halogen⁃Free Intumescent Flame⁃Retardant Ethylene⁃Vinyl Acetate Copolymer System Based on Organic Montmorillonite and Graphene Nanosheets［J］. Journal of Applied Polymer Science， 2018， 135（23）： 46361.
4	YURDDASKAL M，CELIK E. Effect of Halogen⁃Free Nanoparticles on the Mechanical， Structural，Thermal and Flame Retardant Properties of Polymer Matrix Composite［J］. Composite Structures， 2018， 183：381⁃388.
5	YANG B，CHEN Y H，ZHANG M D， et al. Synergistic and Compatibilizing Effect of Octavinyl Polyhedral Oligomeric Silsesquioxane Nanoparticles in Polypropylene/Intumescent Flame Retardant Composite System［J］. Composites Part A： Applied Science and Manufacturing， 2019， 123：46⁃58.
6	CHEN X L，SONG W R，LIU J B， et al. Synergistic Flame⁃Retardant Effects Between Aluminum Hypophosphite and Expandable Graphite in Silicone Rubber Composites［J］. Journal of Thermal Analysis and Calorimetry， 2015， 120（3）： 1 819⁃1 826.
7	张延奎，吴昆，张卡，等. 双层包裹聚磷酸铵微胶囊合成及其在环氧树脂中阻燃研究［J］. 高分子学报， 2012（7）： 759⁃765.
	ZHANG Y K， WU K， ZHANG K， et al. Synthesis of Double⁃coated Ammonium Polyphosphate Microcapsules and Their Flame Retardancy in Epoxy Resin［J］. Acta Polymerica Sinica， 2012（7）： 759⁃765.
8	WU K，SONG L，WANG Z， et al. Preparation and Characterization of Double Shell Microencapsulated Ammonium Polyphosphate and Its Flame Retardance in Polypropylene［J］. Journal of Polymer Research， 2009， 16（3）： 283⁃294.
9	NI J X，TAI Q L，LU H D， et al. Microencapsulated Ammonium Polyphosphate with Polyurethane Shell： Preparation， Characterization， and Its Flame Retardance in Polyurethane［J］. Polymers for Advanced Technologies， 2010， 21（6）： 392⁃400.
10	LIN Y，JIANG S，HU Y， et al. Hybrids of Aluminum Hypophosphite and Ammonium Polyphosphate： Highly Effective Flame Retardant System for Unsaturated Polyester Resin［J］. Polymer Composites， 2018， 39（5）： 1 763⁃1 770.
11	DING H Y，HUANG K，LI S H， et al. Flame Retardancy and Thermal Degradation of Halogen⁃Free Flame⁃Retardant Biobased Polyurethane Composites Based on Ammonium Polyphosphate and Aluminium Hypophosphite［J］. Polymer Testing， 2017， 62：325⁃334.
12	ZHAO G D，PAN Z L，LU C X， et al. Halogen⁃Free Intumescent Flame Retardant Acrylonitrile⁃Butadiene⁃Styrene/Poly（ethylene terephthalate） Blends［J］. Journal of Applied Polymer Science， 2010， 118（3）： 1 589⁃1 597.
13	JIANG Z W，LIU G S. Microencapsulation of Ammonium Polyphosphate with Melamine⁃Formaldehyde⁃Tris（2⁃hydroxyethyl）isocyanurate Resin and Its Flame Retardancy in Polypropylene［J］. RSC Advances， 2015， 107（5）： 88 445⁃88 455.

[1]	WU Wei, HU Huanbo, SHEN Hui, ZHAO Tianyu. Dual⁃synergistic effect of 4A zeolite and Ca⁃Mg⁃Al hydrotalcite on intumescent flame retardant PP and its mechanism [J]. China Plastics, 2022, 36(7): 1-7.
[2]	YU Changyong, XIN Zhong. Effect of α/β complex nucleating agent based on hexahydrophthalate on properties of polypropylene [J]. China Plastics, 2022, 36(7): 121-128.
[3]	WEI Simiao, SHAO Lushan, XU Zhun, LIU Yanting, ZHAO Siheng, XU Bo. Flame⁃retardant performance of PA6 modified with hypophosphite/siloxane bi⁃functional compound and diethyl aluminum hypophosphite compound [J]. China Plastics, 2022, 36(7): 129-135.
[4]	LIU Yi, SUN Wei, QU Guoxing, WANG Ye, YUAN Ning, YANG Shaolin, XU Xia, CHANG Xiaoyi, ZHANG Yufei. Structure and performance analysis of transparent polypropylene special material for thin⁃wall injection molding [J]. China Plastics, 2022, 36(7): 37-43.
[5]	CHEN Ke, LIU Mingfei, ZHAO Biao, PAN Kai. Research progress in flame retardancy and ablation resistance of silicone⁃modified polymeric materials [J]. China Plastics, 2022, 36(6): 149-154.
[6]	SUN Wei, LIU Yi, LIAO Yunlong, CHEN Junjia. Study on influence factors for determination of ethylene content in polypropylene powder [J]. China Plastics, 2022, 36(6): 54-59.
[7]	LI Mengqi, CHEN Yajun. Research progress in flame⁃retardancy of poly（lactic acid） with nanomaterials [J]. China Plastics, 2022, 36(4): 102-114.
[8]	XU Weihua, ZHENG Yu, SHEN Xiangyang, ZHANG Yan, LIU Juwen, YAN Shijing. Effects of different POSS on properties of phosphorus⁃silicon synergistic flame retardant epoxy resin [J]. China Plastics, 2022, 36(4): 115-120.
[9]	LIU Chuan, XU Miaojun, WANG Jingchun, LI Bin. Effect of expandable graphite on flame retardant performance of vinyl silicone rubber [J]. China Plastics, 2022, 36(4): 15-18.
[10]	WANG Qingsong. Development of glass⁃fiber⁃reinforced polypropylene with high strength and low VOC [J]. China Plastics, 2022, 36(4): 30-34.
[11]	WANG Fuyu, GUO Jinqiang, ZHANG Yuxia. In⁃situ fibrillation methods of polymer blends and their application in PP⁃based blends [J]. China Plastics, 2022, 36(3): 146-156.
[12]	LI Rui, JIANG Yanfeng, WU Shuang, AN Yanjie, JIANG Zeyu, ZHANG Mingqiang. Microstructure and thermal characterization of polypropylene special material for cast films through temperature rising elution fractionation [J]. China Plastics, 2022, 36(3): 53-57.
[13]	CAO Zhifeng, ZHAO Lipin, HE Ting, MA Baijun. Preparation and properties of five⁃layer co⁃extrusion barrier films [J]. China Plastics, 2022, 36(3): 64-68.
[14]	ZHAI Yujiao, XIN Chunling, HE Yadong, YAN Baorui, QIAO Linjun. Study on process parameters for filling process of polypropylene microcellular injection molding under supercritical N₂ [J]. China Plastics, 2022, 36(3): 69-74.
[15]	SONG Renda, WU Gaojian, CHEN Junxiang, ZHANG Youchen, YANG Weimin, XIE Pengcheng. Preparation and its electromagnetic shielding performance of PP/PET/CNTs foaming composites [J]. China Plastics, 2022, 36(2): 1-7.