Study on Anti⁃thermal Oxidative Aging Mechanism of Polyamide 6/Short⁃cut Carbon Fiber/Copper Salt Composites

doi:10.19491/j.issn.1001-9278.2021.07.002

Abstract

Abstract:

Polyamide 6 （PA6）/short-cut carbon fiber （SCF）/copper salt/potassium（KI） composites were prepared using a melt blending method. The heat-resistant oxidative aging mechanisms of copper salt/KI system for the PA6 composi-tes were studied using electronic universal testing machine， differential scanning calorimetry （DSC）， X?ray polycrystalline diffractometer （XRD） and X-ray photoelectron spectrometer （XPS）. The results indicated that there is little effect from a single copper salt or KI on the thermal-oxidative aging resistance of PA6. The copper salt/KI compounding system can effectively improve the retention rate of tensile strength for the PA6/SCF composites after heat aging. The carbon fiber has a certain capability to capture free radicals. The addition of copper salt， KI and SCF significantly prolonged the oxidation induction time of PA6. The anti-thermal oxidative aging mechanism of the copper salt/KI system is proposed as follows： firstly， KI converts the divalent copper in the polyamide matrix into monovalent copper， then excessive KI can react with monovalent copper to form Cupric diiodide ion ［CuI₂］^-. ［CuI₂］^-ions have strong reducibility， which consumes free radicals generated during the aging process of PA6， delaying the thermal degradation process of PA6 accordingly.

Key words: resistance to thermal-oxidative aging, polyamide 6, copper salt, potassium iodide, coordination ion, carbon fiber

CLC Number:

TQ327.3

LIU Yao, DING Jianfeng, XIA Zhean, LI Xinxin. Study on Anti⁃thermal Oxidative Aging Mechanism of Polyamide 6/Short⁃cut Carbon Fiber/Copper Salt Composites[J]. China Plastics, 2021, 35(7): 12-17.

Figures/Tables 7

材料组成	配比（质量比）
PA6/SCF	95/5
PA6/SCF/CuCl₂	95/5/0.1
PA6/SCF/CuCl₂/KI	95/5/0.1/0.6
PA6/SCF/KI	95/5/0.6
PA6/SCF/Cu（OAc）₂/KI	95/5/0.1/0.6
PA6/SCF/CuI/KI	95/5/0.1/0.6

Tab. 1. Formulation of PA6/SCF/copper salt/KI composites

Fig.1. Tensile strength retention rate of PA6 composite material under different aging time

Fig.2. Comparison chart of OIT of PA6 composite

Fig.3. Spectrogram of different components in methyl violet/H2SO4 solution

Fig.4. XPS spectrum diagram of PA6/SCF/CuCl2/KI composites （Cu2p）

Cu类型	2p_3/2	2p_1/2	卫星峰
标准Cu⁺（Ⅰ）	932	952	-
标准Cu²⁺（Ⅱ）	934	954	942
试样Cu	932.2	952.1	-

Tab.2. Comparison of the peak between the sample and the standard valence state Cu

Fig.5. XRD spectrum diagram of PA6/copper salt/KI material

References 27

1	CERRUTI P， CARFAGNA C， RYCHLÝ J， et al. Chemiluminescence from Oxidation of Polyamide 6，6. I. The Oxidation of Pure Polyamide［J］. Polymer Degradation Stability， 2003， 82（3）： 477⁃485.
2	CARROCCIO S， PUGLISI C， SCALTRO G， et al. Matrix⁃assisted Laser Desorption/Ionization Time⁃of⁃Flight Investigation of Nylon 6 and Nylon 66 Thermo⁃Oxidation Products［J］. European Journal of Mass Spectrometry， 2007， 13（6）： 397⁃408.
3	GIJSMAN P， MEIJERS G， VITARELLI G. Comparison of the UV⁃degradation Chemistry of Polypropylene， Polyethylene， Polyamide 6 and Polybutylene Terephthalate［J］. Polymer Degradation Stability， 1999， 65（3）： 433⁃441.
4	LÁNSKÁ B， ŠEBENDA J. The Effect of Carboxylic and Basic End⁃groups on the Thermo⁃oxidation of Hydrolytic Polymers of Lactams［J］. European Polymer Journal， 1986， 22（3）： 199⁃202.
5	BERNSTEIN R， DERZON D K， GILLEN K T. Nylon 6.6 Accelerated Aging Studies： Thermal–oxidative Degradation and Its Interaction with Hydrolysis［J］. Polymer Degradation Stability， 2005， 88（3）： 480⁃488.
6	蔡琤，易国斌，陈旭东. 尼龙老化机理研究进展［J］. 合成材料老化与应用， 2013， 42（4）： 42⁃47.
	CAI C， YI G B， CHEN X D. The Development of Study on Nylon Ageing Mechanism［J］. Synthetic Materials Aging and Application， 2013， 42（4）： 42⁃47.
7	SIEGMANN A， BARAAM Z. Nylon⁃6 Containing Metal Halides II： Tensile Properties［J］. Polymer Engineering & Science， 1981， 21（4）： 223⁃226.
8	GUPTA M C， JAIS A T. Effect of Metal Oxides on the Kinetics of Thermal Oxidative Degradation of Nylon⁃6［J］. Thermochimica Acta， 1993， 230：155⁃165.
9	LÁNSKÁ B， MATISOVÁ⁃RYCHLÁ L， RYCHLÝ J. Stabilization of Polyamides IV. Thermo⁃oxidation of Hexano⁃6⁃lactam in the Presence of Alkali Metal Salts［J］. Polymer Degradation Stability， 2005， 87（2）： 361⁃373.
10	LÁNSKÁ B， MATISOVÁ⁃RYCHLÁ L， RYCHLÝ J. Stabilization of Polyamides. V. Thermo⁃oxidation of Hexa⁃no⁃6⁃lactam in the Presence of Copper Salts［J］. Polymer Degradation Stability， 2005， 89（3）： 534⁃544.
11	KELKAR D S， BHAT N V. Investigation of Structural and Mechanical Properties of Copper‐chloride‐doped Nylon‐6 films. I. Structure［J］. Journal of Applied Polymer Scien⁃ce， 1991， 43（1）： 191⁃195.
12	SIEGMANN A， BARAAM Z. Effect of Metal Halides on the Glass Transition Temperature of Nylon⁃6［J］. Die Makromolekulare Chemie， Rapid Communications， 1980， 1（2）： 113⁃117.
13	BHAT N V， KELKAR D S. Investigation of Electrical Conductivity of Nylon⁃6 Films Doped with Copper Chloride［J］. Journal of Physics D： Applied Physics， 1990， 23（7）： 899⁃902.
14	DUNN P， SANSOM G F. The Stress Cracking of Polya⁃mides by Metal Salts. Part II. Mechanism of Cracking［J］. Journal of Applied Polymer Science， 1969， 13（8）： 1 657⁃1 672.
15	JANSSEN K， GIJSMAN P， TUMMERS D. Mechanistic Aspects of the Stabilization of Polyamides by Combinations of Metal and Halogen Salts［J］. Polymer Degradation Stability， 1995， 49（1）： 127⁃133.
16	刘杰，周金龙，吴盾，等. 高温热氧老化对尼龙66结晶与蠕变性能的影响［J］. 高分子材料科学与工程， 2016， 32（1）： 94⁃99.
	LIU J， ZHOU J L， WU D， et al. Effect of High⁃temperature Thermal Oxidative Aging on the Crystallization and Creep Properties of Nylon⁃66［J］. Polymer Materials Scien⁃ce & Engineering， 2016， 32（1）： 94⁃99.
17	CERRUTI P， CARFAGNA C. Thermal⁃oxidative Degradation of Polyamide 6，6 Containing Metal Salts［J］. Polymer Degradation Stability， 2010， 95（12）： 2 405⁃2 412.
18	曲日华，王立岩，关冲，等. 碳纤维增强尼龙66复合材料的热性能［J］. 塑料， 2020， 49（6）： 45⁃49.
	QU R H， WANG L Y， GUAN C， et al. Carbon Fiber Reinforced Nylon 66 Thermal Properties of Composite［J］. Plastics， 2020， 49（6）： 45⁃49.
19	王大中. 玻纤增强尼龙体系体积拉伸流变共混制备及其结构性能研究［D］. 广州：华南理工大学， 2018.
20	王城. 金属配位交联高性能聚合物的制备及性能研究［D］. 绵阳：西南科技大学， 2018.
21	梁惠霞，张东红，张云霄. 汽车用增韧尼龙6的热氧老化研究［J］. 工程塑料应用， 2009， 37（9）： 71⁃74.
	LIANG H X， ZHANG D H， ZHANG Y X. Study on Thermal Oxidative Aging of Toughening Polyamide and Applied to Automobile［J］. Engineering Plastics Application， 2009， 37（9）： 71⁃74.
22	高立花，叶林. 尼龙6湿热老化寿命预测［J］. 高分子材料科学与工程， 2015， 31（5）： 111⁃114.
	GAO L H， YE L. Service Life Prediction of Nylon 6 Under Hydrothermal Ageing［J］. Polymer Materials Science & Engineering， 2015， 31（5）： 111⁃114.
23	FOCKE W W， WESTHUIZEN I. Oxidation Induction Time and Oxidation Onset Temperature of Polyethylene in Air［J］. Journal of Thermal Analysis and Calorimetry， 2010， 99（1）： 285⁃293.
24	汪灵骥，尹波，杨鸣波，等. 氧化石墨烯对聚酰胺6热氧老化性能的影响［J］. 塑料工业， 2018， 46（4）： 59⁃62.
	WANG L J， YIN B， YANG M B， et al. The Influence of Graphene Oxide to Thermal Oxidative Aging Performance of Polyamide 6［J］. China Plastics Industry， 2018， 46（4）： 59⁃62.
25	黄亚江，叶林，廖霞，等. 复杂条件下高分子材料老化规律、寿命预测与防治研究新进展［J］. 高分子通报， 2017（10）： 52⁃63.
	HUANG Y J， YE L， LIAO X， et al. The Degradation Behavior， Service Lifetime Prediction and Stabilization Strategy of Polymeric Materials under Complex Condition［J］. Polymer Bulletin， 2017（10）： 52⁃63.
26	杨长龙，郑薇，卞俭俭. 炭黑对过氧化物交联聚乙烯性能影响的研究［J］. 复合材料科学与工程， 2016（6）： 44⁃47.
	YANG C L， ZHENG W， BIAN J J. The Effects of Carbon Black on The Property of Peroxide Crosslinked Polyethylene ［J］. Composites Science and Engineering， 2016（6）： 44⁃47.
27	KHALAKHAN I， VOROKHTA M， XIE X X， et al. On the Interpretation of X⁃ray Photoelectron Spectra of Pt⁃Cu Bimetallic Alloys［J］. Journal of Electron Spectroscopy and Related Phenomena， 2021， 246： 147027.

[1]	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.
[2]	FENG Bingtao, WANG Xiaoke, ZHANG Xin, SUN Guohua, WANG Dianlong, HOU Lianlong, MA Jinsong. Preparation and application of continuous carbon⁃fiber⁃reinforced thermoplastic composites [J]. China Plastics, 2022, 36(7): 165-173.
[3]	CHEN Sheng, LIANG Yingchao, WU Fangjuan, FANG Hui, FAN Xinfeng, CHEN Hui, WANG Yonggang. Preparation and interfacial modification of polyamide 6/bidirectional warp⁃knitted glass fiber composites [J]. China Plastics, 2022, 36(5): 24-28.
[4]	HE Hezhi, XU Li, YANG Yike. Effect of prestress on mechanical properties of PC/CF laminates [J]. China Plastics, 2022, 36(4): 1-5.
[5]	XU Rongxia, WEI Gang, WEI Lilan, WU Jiecui, JIANG Yujiang. Friction and wear properties of PE⁃UHMW modified with nano⁃SiO₂ and PA6 [J]. China Plastics, 2022, 36(4): 47-52.
[6]	ZHANG Jiufu, LUO Kaiqiang, XU Jun, GUO Baohua. Study on comprehensive properties and influencing factors of long glass fiber reinforced PA66 composites [J]. China Plastics, 2022, 36(3): 1-8.
[7]	YU Zhixing, LI Yingcheng, WANG Hongxue, PANG Xinlei, WANG Yuyao. Study on laser direct structuring materials based on polyamide 6 and polycarbonate and their fabrication of parts with heterostructure [J]. China Plastics, 2022, 36(2): 8-12.
[8]	YANG Zheng, WANG Zhenhua, LU Shike, LIU Yang, FANG Xiaoming, LI Jiantong, LIU Baoying, DING Tao. Synergistic effect of zinc borate and aluminum diethylphosphinate on flame retardancy of PA6 [J]. China Plastics, 2022, 36(1): 120-127.
[9]	FANG Mei, TAN Kunlun, TAN Yuan, XU Jingwei, HUANG Ming, ZHANG Na. Effect of Heat Treatment on Mechanical Properties of EP/CF and EP/CF/GF [J]. China Plastics, 2021, 35(9): 21-26.
[10]	LU Weixin, LU Chong, WANG Bin, HU Jing, WU Jingjing, ZHOU Qinpeng. Effect of Epoxy Modifiers on Properties of PA6/EVOH Blends [J]. China Plastics, 2021, 35(9): 8-14.
[11]	JIAN Ranran, YANG Weimin, MOHINI Sain. Study on Chemical Foaming Properties of Recycled⁃Carbon⁃Fiber⁃Reinforced Polystyrene Through Torsion Extrusion [J]. China Plastics, 2021, 35(8): 88-93.
[12]	JIAO Jiali, YANG Weimin, GAO Xiaodong, SONG Lijian, CHENG Lisheng. Mechanism Analysis of Carbon Fiber Prepared by Recycled Polyethylene⁃Template Method [J]. China Plastics, 2021, 35(8): 94-99.
[13]	LYU Qiang. Preparation of Glass⁃fiber Reinforced Polyamide 6 with Halogen⁃free Flame Retardant and Permanent Antistatic Performance [J]. China Plastics, 2021, 35(7): 58-62.
[14]	LU Zhangxiang, SONG Ge. Effect of Hybrid Fiber Content on Friction and Wear Properties of Resin⁃based Friction Materials [J]. China Plastics, 2021, 35(6): 20-25.
[15]	HUANG Zhichao, LUO Qiang, LAI Jiamei, LIU Shuaihong. Low⁃velocity Impact and Damage Detection of Epoxy/Glass and Carbon Fiber Composite Plates [J]. China Plastics, 2021, 35(6): 46-52.