Preparation and properties of nano-ZnO/bio-based nylon 612 nano-composite antibacterial film
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摘要: 细菌滋生将缩短食品货架周期,对人体健康产生负面影响,因此开展抗菌包装膜的研究十分重要。本文采用γ-氨丙基三乙氧基硅烷偶联剂(KH550)改性了纳米氧化锌(ZnO),并将改性后的纳米氧化锌(m-ZnO)与尼龙612 (PA612)进行熔融共混制备复合材料,最终采用挤出流延制备了m-ZnO/PA612纳米复合抗菌薄膜。采用FTIR对改性前后的ZnO进行表征,证明了KH550成功接枝到ZnO上。通过SEM、DSC、TGA、平板计数法等测试手段对ZnO的分散及复合材料的结晶性能、热性能、抗菌性能进行了研究。结果表明:m-ZnO在PA612基体中分散良好。m-ZnO可以作为成核剂提高PA612的结晶度,m-ZnO的含量为2wt%时,其结晶度提高了4.1%。m-ZnO对PA612有增强作用,m-ZnO的添加量为2wt%时,m-ZnO/PA612纳米复合薄膜的拉伸强度较纯PA612提高了15%。m-ZnO的存在赋予了PA612抗菌性能,m-ZnO/PA612纳米复合薄膜对大肠杆菌和金黄色葡萄球菌均有很好的抗菌效果,且随着m-ZnO含量的增大,抗菌率增大,m-ZnO的质量分数为4wt%时,对大肠杆菌的抗菌率为93.25%,对金黄色葡萄球菌的抗菌率为91.03%。
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关键词:
- 尼龙612 /
- γ-氨丙基三乙氧基硅烷 /
- 纳米氧化锌 /
- 抗菌 /
- 纳米复合薄膜
Abstract: Bacterial growth can shorten the shelf life of food and exert a negative effect on human health, therefore it is of great importance to conduct research on anti-bacterial films. Herein, the γ-aminopropyltriethoxysilane coupling agent (KH550) was used to modify nano-zinc oxide, and the modified nano-zinc oxide (m-ZnO) was melt-blended with nylon 612 (PA612) to prepare m-ZnO/PA612 nanocomposite, followed by the fabrication of the antibacterial film through extrusion film casting process. The FTIR was used to characterize the nano-zinc oxide before and after the modification, which proved that KH550 was successfully grafted onto the nano-zinc oxide. Through SEM, DSC, TGA, plate counting method, and other test methods, the dispersibility of nano-zinc oxide and the crystallization performance, thermal performance, and antibacterial properties of composite materials were studied. The results show that the m-ZnO is well dispersed in the PA612 matrix. The m-ZnO can be used as a nucleating agent to increase the crystallinity of PA612. When the content of m-ZnO is 2wt%, the crystallinity is increased by 4.1%. Moreover, the m-ZnO exhibits a reinforcing effect on PA612. When the addition amount of m-ZnO is 2wt%, the tensile strength of the m-ZnO/PA612 nanocomposite film is 15% higher than that of pure PA612. The presence of m-ZnO gives PA612 antibacterial properties. m-ZnO/PA612 nanocomposite film has a good inhibitory effect on Escherichia coli and Staphylococcus aureus. With the increase of m-ZnO content, the antibacterial rate increases, when the mass fraction of m-ZnO is 4wt%, the antibacterial rate against Escherichia coli is 93.25%, and the antibacterial rate against Staphylococcus aureus is 91.03%.-
Key words:
- nylon 612 /
- γ-aminopropyltriethoxysilane /
- nano-zinc oxide /
- antibacterial /
- nanocomposite film
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表 1 不同ZnO含量的ZnO/PA612抗菌复合膜
Table 1. ZnO/PA612 antibacterial composite films with different ZnO content
Sample Mass fraction/wt% PA612 m-ZnO ZnO PA612 100 0 0 0.5wt%m-ZnO/PA612 99.5 0.5 0 2wt%
ZnO/PA61298 0 2 2wt%m-ZnO/PA612 98 2 0 4wt%m-ZnO/PA612 96 4 0 6wt%m-ZnO/PA612 94 6 0 Notes: m-ZnO—Modified nano zinc oxide; ZnO—Unmodified nano zinc oxide; PA612—Nylon 612. 表 2 PA612及不同m-ZnO含量的PA612纳米复合材料的DSC热分析数据
Table 2. DSC thermal analysis data of PA612 and PA612 nanocomposites with different m-ZnO contents
Sample Tm/℃ Tc/℃ ΔHm/(J·g−1) Xc/% PA612 222.86 186.26 61.22 23.73 0.5wt%m-ZnO/PA612 220.37 187.09 70.68 27.53 2wt%m-ZnO/PA612 221.67 187.34 70.36 27.83 4wt%m-ZnO/PA612 221.29 186.99 66.99 26.93 6wt%m-ZnO/PA612 220.97 186.14 65.61 26.88 Notes: Tm—Melting peak temperature; Tc—Crystallization peak temperature; △Hm—Melting enthalpy; Xc—Crystallinity. 表 3 PA612及不同m-ZnO含量的PA612纳米复合材料的热稳定性
Table 3. Thermal stability of PA612 and PA612 nanocomposites with different m-ZnO contents
Sample T5%/℃ T50%/℃ Char yield at 600℃/wt% PA612 398.9 450.0 2.3 0.5wt%m-ZnO/PA612 400.4 446.0 2.7 2wt%m-ZnO/PA612 397.2 443.0 3.5 4wt%m-ZnO/PA612 399.3 446.7 4.7 6wt%m-ZnO/PA612 398.6 446.3 7.8 Notes: T5% and T50%—Temperature when the weight loss of the samples is 5wt% and 50wt%, respectively. 表 4 PA612及不同m-ZnO含量的PA612纳米复合材料的拉伸性能
Table 4. Tensile properties of PA612 and PA612 nanocomposites with different m-ZnO contents
Sample Tensile stress/MPa Young’s modulus/MPa Elongation at break/% PA612 93.95±5.55 685.11±50.97 392.77±13.70 0.5wt%m-ZnO/PA612 93.06±4.56 543.66±39.20 378.30±11.08 2wt%m-ZnO/PA612 108.13±1.76 889.70±60.78 305.23±10.13 4wt%m-ZnO/PA612 84.31±8.35 422.97±94.12 371.85±27.97 6wt%m-ZnO/PA612 83.06±10.85 486.79±71.10 325.38±32.66 表 5 PA612及不同m-ZnO含量的PA612纳米复合材料膜对大肠杆菌的抑菌活性
Table 5. Antibacterial activity of PA612 and PA612 nanocomposites with different m-ZnO contents membranes against Escherichia coli
Sample Bacteria concentration/
(CFU·mL−1)Antibacterial rate R/% PA612 5.48×106 0.00 0.5wt%m-ZnO/PA612 3.89×106 29.01 2wt%ZnO/PA612 1.43×106 73.91 2wt%m-ZnO/PA612 5.30×105 90.33 4wt%m-ZnO/PA612 3.70×105 93.25 6wt%m-ZnO/PA612 2.50×105 95.44 表 6 PA612及不同m-ZnO含量的PA612纳米复合材料膜对金黄色葡萄球菌的抑菌活性
Table 6. Antibacterial activity of PA612 and PA612 nanocomposites with different m-ZnO contents membranes against Staphylococcus aureus
Sample Bacteria concentration/
(CFU·mL−1)Antibacterial
rate R/%PA612 5.35×106 0.00 0.5wt%m-ZnO/PA612 3.60×106 32.71 2wt%ZnO/PA612 1.73×106 67.66 2wt%m-ZnO/PA612 9.40×105 82.43 4wt%m-ZnO/PA612 4.80×105 91.03 6wt%m-ZnO/PA612 3.60×105 93.27 -
[1] FUNK I, RIMMEL N, SCHORSCH C, et al. Production of dodecanedioic acid via biotransformation of low cost plant-oil derivatives using Candida tropicalis[J]. Journal of Industrial Microbiology and Biotechnology,2017,44(10):1491-1502. doi: 10.1007/s10295-017-1972-6 [2] TYUFTIN A A, KERRY J P. Review of surface treatment methods for polyamide films for potential application as smart packaging materials: Surface structure, antimicrobial and spectral properties[J]. Food Packaging and Shelf Life,2020,24:100475. doi: 10.1016/j.fpsl.2020.100475 [3] WU Y, HUANG A, FAN S, et al. Crystal structure and mechanical properties of uniaxially stretched PA612/SiO2 films[J]. Polymers,2020,12(3):711. doi: 10.3390/polym12030711 [4] WADI V S, JENA K K, HALIQUE K, et al. Linear sulfur-nylon composites: Structure, morphology, and antibacterial activity[J]. ACS Applied Polymer Material,2020,2(2):198-208. doi: 10.1021/acsapm.9b00754 [5] RYŠÁNEK P, MALÝ M, ČAPKOVÁ P, et al. Antibacterial modification of nylon-6 nanofibers: Structure, properties and antibacterial activity[J]. Journal of Polymer Research,2017,24(11):1-10. doi: 10.1007/s10965-017-1365-6 [6] TANG L, WANG D Y, XU Q S, et al. Preparation and characterization of antibacterial nylon 6 fiber[J]. Materials Science Forum,2017,898:2254-2262. doi: 10.4028/www.scientific.net/MSF.898.2254 [7] VENKATRAM M, NARASIMHA MURTHY H N R, GAIKWAD A, et al. Antibacterial and flame retardant properties of Ag-MgO/nylon 6 electrospun nanofibers for protective applications[J]. Clothing and Textiles Research Journal,2018,36(4):296-309. doi: 10.1177/0887302X18783071 [8] ROHAETI E, RAKHMAWATI A. Application of Terminalia catappa in preparation of silver nanoparticles to develop antibacterial Nylon[J]. Oriental Journal of Chemistry,2017,33:2905-2912. doi: 10.13005/ojc/330625 [9] OMER R A, GHENI A I, OMAR K A, et al. Antimicrobial activity of nylon nanocomposites against Staphylococcus aureus and Escherichia coli bacteria[J]. Science Journal of University of Zakho,2019,7(4):138-143. doi: 10.25271/sjuoz.2019.7.4.631 [10] WANG Z, ZHANG L, LIU Z, et al. The antibacterial polyamide 6-ZnO hierarchical nanofibers fabricated by atomic layer deposition and hydrothermal growth[J]. Nanoscale Research Letters,2017,12(1):1-8. doi: 10.1186/s11671-016-1773-2 [11] TANG Q, WANG K, REN X, et al. Preparation of porous antibacterial polyamide 6 (PA6) membrane with zinc oxide (ZnO) nanoparticles selectively localized at the pore walls via reactive extrusion[J]. Science of the Total Environment,2020,715:137018. doi: 10.1016/j.scitotenv.2020.137018 [12] THOKALA N, KEALEY C, KENNEDY J, et al. Characterisation of polyamide 11/copper antimicrobial composites for medical device applications[J]. Materials Science and Engineering: C,2017,78:1179-1186. doi: 10.1016/j.msec.2017.03.149 [13] SIRELKHATIM A, MAHMUD S, SEENI A, et al. Review on zinc oxide nanoparticles: Antibacterial activity and toxicity mechanism[J]. Nano-micro Letters,2015,7(3):219-242. doi: 10.1007/s40820-015-0040-x [14] QI K, CHENG B, YU J, et al. Review on the improvement of the photocatalytic and antibacterial activities of ZnO[J]. Journal of Alloys and Compounds,2017,727:792-820. doi: 10.1016/j.jallcom.2017.08.142 [15] LI S C, LI Y N. Mechanical and antibacterial properties of modified nano-ZnO/high-density polyethylene composite films with a low doped content of nano-ZnO[J]. Journal of Applied Polymer Science,2010,116(5):2965-2969. doi: 10.1002/app.31802 [16] KIM I, VISWANATHAN K, KASI G, et al. Poly(lactic acid)/ZnO bionanocomposite films with positively charged ZnO as potential antimicrobial food packaging materials[J]. Polymers,2019,11(9):1427. doi: 10.3390/polym11091427 [17] LI Y, XU W, ZHANG G. Effect of coupling agent on nano-ZnO modification and antibacterial activity of ZnO/HDPE nanocomposite films[J]. IOP Conference Series: Materials Science and Engineering,2015,87:012054. doi: 10.1088/1757-899X/87/1/012054 [18] LI Y, YU J, GUO Z. The influence of silane treatment on Nylon 6/nano-SiO2 in situ polymerization[J]. Journal of Applied Polymer Science,2002,84(4):827-834. doi: 10.1002/app.10349 [19] 国家化学建筑材料测试中心(材料测试部). 透明塑料透光率和雾度的测定: GB/T 2410—2008[S]. 北京: 中国标准出版社, 2008.National Testing Center of Polymer and Chemical Building Materials (Materials Testing Department). Determination of the luminous transmittance and haze of transparent plastics: GB/T 2410—2008[S]. Beijing: China StandardsPress, 2008(in Chinese). [20] 中华人民共和国卫生部. 塑料—塑料表面抗菌性能试验方法: GB/T 31402—2015[S]. 北京: 中国标准出版社, 2015.Ministry of Health of the People's Republic of China. Plastics—Measurement of antibacterial activity on plastics surfaces: GB/T 31402—2015[S]. Beijing: China Standards Press, 2015(in Chinese). [21] KHURANA N, ARORA P, PENTE A S, et al. Surface modification of zinc oxide nanoparticles by vinyltriethoxy silane (VTES)[J]. Inorganic Chemistry Communications,2021,124:108347. doi: 10.1016/j.inoche.2020.108347 [22] HANG T T X, DUNG N T, TRUC T A, et al. Effect of silane modified nano ZnO on UV degradation of polyurethane coatings[J]. Progress in Organic Coatings,2015,79:68-74. doi: 10.1016/j.porgcoat.2014.11.008 [23] FAN X, YAN Y. Poly (amino acid)/ZnO nanoparticles nanocomposites with enhanced thermal, mechanical, and antibacterial properties[J]. Polymer Bulletin,2020,77(5):2325-2343. doi: 10.1007/s00289-019-02860-6 [24] SHANKAR S, WANG L F, RHIM J W. Incorporation of zinc oxide nanoparticles improved the mechanical, water vapor barrier, UV-light barrier, and antibacterial properties of PLA-based nanocomposite films[J]. Materials Science and Engineering: C,2018,93:289-298. doi: 10.1016/j.msec.2018.08.002 [25] ASANO T, BALTÁ CALLEJA F J, GIR L, et al. Structure and mechanical properties of nylon 612 prepared by temperature slope crystallization. II. Rolling deformation and microhardness of the oriented negative spherulite[J]. Journal of Macromolecular Science, Part B: Physics,1997,36(6):799-812. doi: 10.1080/00222349708212403 [26] SHOJAEIARANI J, BAJWA D, JIANG L, et al. Insight on the influence of nano zinc oxide on the thermal, dynamic mechanical, and flow characteristics of poly(lactic acid)-zinc oxide composites[J]. Polymer Engineering & Science,2019,59(6):1242-1249. doi: 10.1002/pen.25107 [27] MALLAKPOUR S, NOURUZI N. Effect of modified ZnO nanoparticles with biosafe molecule on the morphology and physiochemical properties of novel polycaprolactone nanocomposites[J]. Polymer,2016,89:94-101. doi: 10.1016/j.polymer.2016.02.038 [28] LIU J, WANG Y, MA J, et al. A review on bidirectional analogies between the photocatalysis and antibacterial properties of ZnO[J]. Journal of Alloys and Compounds,2019,783:898-918. doi: 10.1016/j.jallcom.2018.12.330 [29] HU C, GUO J, QU J, et al. Photocatalytic degradation of pathogenic bacteria with AgI/TiO2 under visible light irradiation[J]. Langmuir,2007,23(9):4982-4987. doi: 10.1021/la063626x