Journal of Textile Research ›› 2021, Vol. 42 ›› Issue (07): 11-18.doi: 10.13475/j.fzxb.20210200108

• Invited Column: New Flame Retardant Technology for Textile Materials • Previous Articles     Next Articles

Preparation and properties of synergistic flame retardant copolyamide 6 fiber with phosphaphenanthrene group

LIU Ke, CHEN Shuang, XIAO Ru()   

  1. Key Laboratory of High-Performance Fibers & Products, Ministry of Education, Donghua University, Shanghai 201620, China
  • Received:2021-02-01 Revised:2021-04-21 Online:2021-07-15 Published:2021-07-22
  • Contact: XIAO Ru E-mail:xiaoru@dhu.edu.cn

Abstract:

In order to improve the flame retardancy of polyamide 6 (PA6) fibers,a flame retardant was synthesized by copolymerization with 10-(2,5-dicarboxyl phenoxyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPODP) and combination of molybdenum disulfide (MoS2) or zinc sulfide (ZnS), the flame retardant PA6 fibers were prepared via melt spinning. The structure, properties, and the flame-retardant mechanism of the co-PA6 and its fibers were also studied. The results show that the DOPODP had been introduced into PA6 molecular chains, the flame retardancy of the copolymer was improved, but the melting temperature and crystallization temperature were reduced. The synergistic flame retardant PA6 achieved a V-0 rating according to the UL94 criterion with an LOI value greater than 30%. The study of the flame-retardant mechanism indicated that the DOPODP in PA6 mainly take effects in gas phase, DOPODP could decompose to phosphorus radicals. In addition, with the introduction of synergistic flame retardants, the char content of flame retardant PA6 was increased. Compared with PA6 fiber, the mechanical properties of flame retardant PA6 fibers were decreased, and the LOI value of the fabrics increased.

Key words: polyamide 6, flame retardant agent, molybdenum disulfide, zinc sulfide, copolymerization, flame retardant fiber, functional fiber

CLC Number: 

  • TQ323.6

Fig.1

Preparation process of PA6-DOPODP"

Tab.1

Experiment formula of PA6-DOPODP/MoS2/ZnS "

试样编号 质量分数/%
DOPODP MoS2 ZnS
0# 0 0 0
1# 3 0 0
2# 5 0 0
3# 7 0 0
4# 9 0 0
5# 9 2 0
6# 9 0 2

Fig.2

FT-IR spectra of DOPODP and DOPODP-DMDA salt"

Fig.3

FT-IR spectra of samples"

Fig.4

Structure and NMR spectrum of sample 4#. (a) Structure; (b) 1H-NMR spectrum; (c) 31P-NMR spectrum "

Tab.2

Element analysis results of PA6-DOPODP"

试样
编号
元素含量/% 磷含量/% 反应
比/%
C H N O 理论 实测
0# 63.02 9.94 12.20 14.84
1# 63.13 9.70 11.86 14.99 0.230 0.221 96.09
2# 63.21 9.67 11.89 14.86 0.387 0.371 95.87
3# 63.45 9.53 11.80 14.71 0.536 0.512 95.52
4# 63.59 9.48 11.75 14.55 0.697 0.635 91.10

Tab.3

Relative viscosity, molecular weight and molecular weight distribution of PA6-DOPODP/MoS2/ZnS "

试样编号 相对黏度 数均分子量/(g·mol-1) 多分散性指数
0# 2.52 2.19×104 1.76
1# 2.55 2.27×104 1.79
2# 2.47 2.18×104 1.82
3# 2.45 2.12×104 1.84
4# 2.37 1.92×104 1.97
5# 2.42
6# 2.39

Tab.4

DSC results of PA6-DOPODP/MoS2/ZnS "

试样编号 熔融温度/℃ 熔融焓/(J·g-1) 结晶温度/℃ 结晶度/%
0# 221.3 71.7 182.7 37.6
1# 218.4 56.7 179.4 29.7
2# 214.8 56.3 176.4 29.5
3# 211.5 55.4 171.4 29.1
4# 209.5 52.5 157.9 27.6
5# 210.1 53.4 179.9 28.5
6# 209.1 57.3 166.7 30.6

Tab.5

Vertical burning and LOI values test results"

试样编号 垂直燃烧 LOI值/%
是否引燃脱脂棉 级别
0# V-2 23.5±0.2
1# V-2 24.1±0.2
2# V-2 25.2±0.2
3# V-2 26.5±0.2
4# V-2 27.6±0.2
5# V-0 30.3±0.2
6# V-0 30.7±0.2

Fig.5

HRR curves of PA6-DOPODP/MoS2/ZnS "

Tab.6

Cone calorimetric data"

试样
编号
TTI/
s
p-HRR/
(kW·m-2)
THR/
(MJ·m-2)
av-EHC/
(MJ·kg-1)
SEA/
(m2·kg-1)
残炭
量/%
0# 62 1 132 136 37 210 0.19
4# 51 868 105 28 436 3.11
5# 52 785 92 27 394 6.52
6# 53 766 94 27 366 6.37

Fig.6

Py-GC/MS spectra of DOPODP, sample 0# and 4# "

Tab.7

Thermogravimetry data of PA6-DOPODP/MoS2/ZnS "

试样编号 初始热分解温度/℃ 最大热分解温度/℃ 残炭量/%
0# 380.3 453.3 0.1
1# 374.7 417.9 3.2
2# 370.7 413.3 3.4
3# 368.4 412.8 3.8
4# 365.9 403.1 4.9
5# 366.7 404.3 6.9
6# 367.5 422.1 8.3

Fig.7

SEM images of char residues of samples"

Fig.8

Raman spectra of char residues of sample"

Fig.9

SEM images of surface and cross-section of samples"

Tab.8

Mechanical properties of fibers"

试样编号 断裂强度/(cN·dtex-1) 断裂伸长率/%
0# 4.3 57.8
1# 4.0 66.9
2# 3.7 63.5
3# 3.5 66.3
4# 3.3 55.6
5# 2.6 46.2
6# 2.3 32.3

Tab.9

Flame retardancy of fabrics"

试样
编号
续燃时间/
s
阴燃时间/
s
损毁长度/
cm
是否引燃
脱脂棉
LOI值/
%
0# 31.5 0.0 14.2 22.1±0.2
4# 1.2 0.0 4.7 27.5±0.2
5# 1.3 0.0 3.2 29.3±0.2
6# 1.9 0.0 4.8 29.7±0.2
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