Preparation of three⁃sources⁃in⁃one shell⁃core structural flame retardants and its application in poly（lactic acid）

doi:10.19491/j.issn.1001-9278.2022.09.014

Abstract

Abstract:

Two types of three⁃sources⁃in⁃one shell⁃core structural flame retardants， ammonium polyphosphate （APP）@chitosan （CS）@halloysite （HNT）（ACH） and APP@CS⁃Fe@HNT （ACFH）， were prepared through a self⁃assembly method using water as the solvent， APP as a core， and CS/ferric chloride/HNT composite as a shell. ACFH was employed to improve the flame retardancy of PLA. The composition and structure of ACFH were analyzed using scanning electron microscope and thermogravimetry （TG）. The flame retardancy of PLA composites was characterized using limi⁃ting oxygen index （LOI）， vertical combustion （UL 94）， cone calorimeter （CCT）， and TG⁃FTIR. The results indicated that the flame retardancy of the PLA/15 %ACFH composite was better than that of pure PLA and the PLA/15 %ACH composite. The PLA/15 %ACFH composite exhibited the highest LOI value of 29.5 vol% with a UL 94 classification of V⁃0. Compared to pure PLA， the PLA/1 5%ACFH composite presented a decrease in peak heat release rate and total heat release by 33.5 % and 22.0 %， respectively， and its residual char yield increased by 12.5 wt%. ACFH mainly generated a flame⁃retardant effect in the condensed phase， promoting the formation of a large number of continuous and dense carbon layers in the PLA matrix. The resulting carbon layers acted as a barrier to inhibit the diffusion of oxygen and heat.

Key words: poly（lactic acid）, shell?core, flame retardant, halloysite, chitosan

CLC Number:

TQ321

MENG Xin, WANG Xiaolong, GONG Weiguang, JIN Yi. Preparation of three⁃sources⁃in⁃one shell⁃core structural flame retardants and its application in poly（lactic acid）[J]. China Plastics, 2022, 36(9): 96-104.

Figures/Tables 18

References 28

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样品名称	PLA/%	ACH/%	ACFH/%
纯PLA	100	0	0
PLA/13 %ACH	87	13	0
PLA/15 %ACH	85	15	0
PLA/17 %ACH	83	17	0
PLA/13 %ACFH	87	0	13
PLA/15 %ACFH	85	0	15
PLA/17 %ACFH	83	0	17

样品名称	PLA/%	ACH/%	ACFH/%
纯PLA	100	0	0
PLA/13 %ACH	87	13	0
PLA/15 %ACH	85	15	0
PLA/17 %ACH	83	17	0
PLA/13 %ACFH	87	0	13
PLA/15 %ACFH	85	0	15
PLA/17 %ACFH	83	0	17

样品名称	T_{5 %}/℃	T_max/℃	PHRR/%•℃^-1	残炭量/%
APP	351.5	639.9	1.035	20.4
HNT	455.9	489.4	0.154	85.9
CS	277.8	312.3	0.796	36.0
ACH	293.8	607.3	0.286	40.8
ACFH	279.0	315.0	0.198	57.2

样品名称	T_{5 %}/℃	T_max/℃	PHRR/%•℃^-1	残炭量/%
APP	351.5	639.9	1.035	20.4
HNT	455.9	489.4	0.154	85.9
CS	277.8	312.3	0.796	36.0
ACH	293.8	607.3	0.286	40.8
ACFH	279.0	315.0	0.198	57.2

样品名称	UL 94等级	LOI/%
纯PLA	NR	18.1
PLA/13 %ACH	V⁃2	27.3
PLA/15 %ACH	V⁃2	28.3
PLA/17 %ACH	V⁃0	29.4
PLA/13 %ACFH	V⁃2	27.8
PLA/15 %ACFH	V⁃0	29.5
PLA/17 %ACFH	V⁃0	30.2