基于TD-NMR的PMMA木塑复合材吸湿和吸水研究

doi:10.11938/cjmr20233054

摘要/Abstract

摘要：

本研究采用时域核磁共振（TD-NMR）技术探究聚甲基丙烯酸甲酯（PMMA）木塑复合材在吸湿与吸水过程中水分的状态和自旋-自旋弛豫（T₂）特征．并比较PMMA木塑复合材的阻湿率和拒水率，分析PMMA木塑复合材的阻湿和防水性能与原理．研究对象为浸渍甲基丙烯酸甲酯（MMA）单体聚合生成的PMMA木塑复合材．首先对绝干的PMMA木塑复合材进行核磁共振T₂检测，然后分别进行吸湿和吸水实验，并每隔一段时间测定试件质量及其T₂信号量．结果表明：PMMA木塑复合材的吸湿率和吸水率低于未处理材，具有良好的阻湿和防水性能，且MMA浸渍浓度为100%，浸渍时间为24 h时，在温度为 (40±0.2) ℃相对湿度为 (96.4±0.4)%恒温恒湿环境下木塑复合材吸湿率低于15%，常温下吸水试件的吸水率低于30%．PMMA木塑复合材的吸湿率和吸水率明显降低，T₂峰面积也逐渐减小．这说明木塑复合材内部的PMMA起到了防止水分进入的作用．

关键词: 木塑复合材, 聚甲基丙烯酸甲酯, 时域核磁共振, 弛豫特征, 木材吸湿性

Abstract:

In this study, time-domain nuclear magnetic resonance (TD-NMR) technology was employed to explore the moisture state and spin-spin relaxation (T₂) characteristics of polymethyl methacrylate (PMMA) wood-plastic composites during the moisture absorption and water absorption process. The moisture resistance and water repellency of PMMA wood-plastic composites were compared and analyzed. The experimental samples were PMMA wood-plastic composite material produced by impregnated methyl methacrylate (MMA) monomer polymerization. Firstly, the NMR T₂ test was carried out on the dry PMMA wood-plastic composite, and then the moisture absorption and water absorption experiments were carried out respectively, and the mass of the specimen and its T₂ signal were measured at intervals. The results showed that the moisture absorption rate and water absorption rate of PMMA wood-plastic composite were lower than those of untreated wood, and PMMA had good moisture resistance and water resistance. When the impregnation concentration of MMA was 100 % and the impregnation time reached 24 h, the moisture absorption rate of wood-plastic composites was lower than 15% under the constant temperature of (40±0.2)℃ and relative humidity of (96.4±0.4)%, and the water absorption rate of water-absorbing specimens at room temperature was lower than 30%. At the same impregnation time, with the increase of impregnation concentration of MMA, the moisture absorption rate and water absorption rate of PMMA wood-plastic composites decreased significantly, and the T₂ peak area decreased gradually. This indicates that the PMMA inside the wood-plastic composite material contributes to preventing water from entering.

Key words: wood-plastic composites, PMMA, TD-NMR, relaxation characteristics, moisture absorption of wood

中图分类号:

赵万磊, 赵芝弘, 张明辉, 刘文静. 基于TD-NMR的PMMA木塑复合材吸湿和吸水研究[J]. 波谱学杂志, 2023, 40(4): 448-461.

ZHAO Wanlei, ZHAO Zhihong, ZHANG Minghui, LIU Wenjing. Study on Moisture Absorption and Water Absorption of PMMA Wood-plastic Composites Based on TD-NMR[J]. Chinese Journal of Magnetic Resonance, 2023, 40(4): 448-461.

图/表 10

表1

图1

图2

图3

图4

表2

图5

图6

表3

图7

参考文献 45

[1]	ORMONDROYD G, SPEAR M, CURLING S. Modified wood: review of efficacy and service life testing[J]. Constr Mater, 2015, 168(4): 187-203.
[2]	BI X Q, ZHANG Y, LI P, et al. Poplar impregnation modification and research progress in furniture application[J]. Mater Rep, 2022, 36(21): 21050166-11.
	毕小茜, 张源, 李萍, 等. 杨木浸渍改性及在家具应用中的研究进展[J]. 材料导报, 2022, 36(21): 21050166-11.
[3]	KAMPERIDOU V. Chemical and structural characterization of poplar and black pine wood exposed to short thermal modification[J]. Drvna Ind, 2021, 72(2): 155-167. doi: 10.5552/drvind
[4]	LIU S M, CAO J Z. Changes in chemical composition of thermally modified wood and their influen3cing factors[J]. World Forestry Research, 2022, 35 (6): 56-62.
	刘淑敏, 曹金珍. 热改性木材化学成分变化及其影响因素[J]. 世界林业研究, 2022, 35(6): 56-62.
[5]	RADABUTRA S, KHEMTHONG P, SAENGSUWAN S, et al. Preparation and characterization of natural rubber biobased wood adhesive: effect of total solid content, viscosity, and storage time[J]. Polym Bull, 2020, 77(5): 2737-2747. doi: 10.1007/s00289-019-02881-1
[6]	GUO D K, SHEN X S, YANG S, et al. Mechanism of improving dimensional stability of water-soluble vinyl monomer modified wood[J]. Sci Silvae Sin, 2021, 57(7): 158-165.
	郭登康, 沈晓双, 杨昇, 等. 水溶性乙烯基单体改性木材尺寸稳定性提高机制[J]. 林业科学, 2021, 57(7): 158-165.
[7]	HU X, LI D, LUO B, et al. Weathering characteristics of wood plastic composites compatibilized with ethylene vinyl acetate[J]. BioResources, 2020, 15(2): 3930-3944. doi: 10.15376/biores
[8]	QIU H B, YANG S, HAN Y, et al. Improvement of the performance of plantation wood by grafting water soluble vinyl monomers onto cell walls[J]. ACS Sustainable Chem Eng, 2018, 6(11): 14450-14459 doi: 10.1021/acssuschemeng.8b03112
[9]	CHEN P, LI Y, NISHIYAMA Y, et al. Small angle neutron scattering shows nanoscale PMMA distribution in transparent wood biocomposites[J]. Nano Letters, 2021, 21(7): 2883-2890. doi: 10.1021/acs.nanolett.0c05038 pmid: 33734720
[10]	ZHANG C, MA Y, LIN T, et al. Transparent photochromic wood composites incorporating AgBr nanoparticles for UV-shielding applications[J]. Pap Biomater, 2021, 6(4): 21-29.
[11]	ALQAHTANI S, ALJUHANI E, FELALY R, et al. Development of photoluminescent translucent wood toward photochromic smart window applications[J]. Ind Eng Chem Res, 2021, 60(23): 8340-8350. doi: 10.1021/acs.iecr.1c01603
[12]	YUE D, FU G, JIN Z. Transparent wood prepared by polymer impregnation of rubber wood (Hevea brasiliensis Muell. Arg)[J]. BioResources, 2021, 16(2): 2491-2502. doi: 10.15376/biores
[13]	吴佳敏. 透明木材的合成及微观机理研究[D]. 南京林业大学, 2019.
[14]	DEFOIRDT N, GARDIN S, VAN DEN BULCKE J, et al. Moisture dynamics of WPC and the impact on fungal testing[J]. Int Biodeter Biodegr, 2010, 64(1): 65-72. doi: 10.1016/j.ibiod.2009.07.010
[15]	WU X, LIN Y, GUO J Q, et al. Differentiating Pu-erh raw tea from different geographical origins by ¹H NMR and U-HPLC/Q-TOF-MS combined with chemometrics[J]. J Food Sci, 2021, 86(3): 779-791. doi: 10.1111/jfds.v86.3
[16]	ZHAN J H, HU Q, ZHU Q J, et al. Marker-free yeast cytochrome c conformational change tracking in cytoplasm based on magnetic resonance[J]. Chinses J Magn Reson, 2023, 40 (1): 22-29.
	占建华, 胡琴, 朱勤俊, 等. 基于磁共振的胞浆中无标记酵母细胞色素c构象变化追踪[J]. 波谱学杂志, 2023, 40(1): 22-29.
[17]	ZHANG W, WU Y M, CUI W P, et al. Nuclear magnetic resonance porosity correction method for heavy oil reservoirs[J]. Chinese J Magn Reson, 2021, 38 (2): 204-214.
	张伟, 吴意明, 崔维平, 等. 稠油储层核磁共振孔隙度校正方法[J]. 波谱学杂志, 2021, 38(2): 204-214.
[18]	ZHANG R, WANG W, GAO Y, et al. Sensitivity analysis of T₂-T₁ two-dimensional nuclear magnetic resonance measurement parameters in shale oil reservoirs[J]. Chinese J Magn Reson, 2023, 40(2): 122-135.
	张融, 王伟, 高怡, 等. 页岩油储层T₂-T₁二维核磁共振测量参数敏感性分析[J]. 波谱学杂志, 2023, 40(2): 122-135.
[19]	NIU X X, BAI Z J, YANG Y, et al. Quantitative monitoring of photocatalytic Cr (VI) reduction reaction by in-situ low-field nuclear magnetic resonance relaxation method[J]. Chinese J Magn Reson, 2021, 38 (3): 403-413.
	牛星星, 白志杰, 杨翼, 等. 原位低场核磁共振弛豫法定量监测光催化Cr(VI)还原反应[J]. 波谱学杂志, 2021, 38(3): 403-413.
[20]	HU Y F, JIN C W. Conformational dynamics in GPCR signaling by NMR[J]. Magn Reson Lett, 2022, 2(3):139-146.
[21]	LI J Y. MA ER N. Characterization of water in wood by time-domain nuclear magnetic resonance spectroscopy (TD-NMR): A Review[J]. Forests, 2021, 12 (7):886. doi: 10.3390/f12070886
[22]	ROSTOM L, COUYTIER-MURIAS D, RODTS S, et al. Investigation of the effect of aging on wood hygroscopicity by 2D ¹H NMR relaxometry[J]. Holzforschung, 2020, 74(4): 400-411. doi: 10.1515/hf-2019-0052
[23]	LI J Y, MA ER N. Effects of heat treatment and delignification on the hygroscopic limit and cell wall saturation of southern pine wood[J]. Journal of Forestry Engineering, 2021, 6(03): 61-68.
	李京予, 马尔妮. 热处理及脱木质素对南方松木材吸湿极限与细胞壁饱和状态的影响[J]. 林业工程学报, 2021, 6(03): 61-68.
[24]	LI J Y, MA ER N, 2D time-domain nuclear magnetic resonance (2D TD-NMR) characterization of cell wall water of Fagus sylvatica and Pinus taeda L[J]. Cellulose, 2022, 29(16): 8491-8508. doi: 10.1007/s10570-022-04789-y
[25]	PASSARINI L, MALVEAU C, HERNANDEZ R E. Distribution of the equilibrium moisture content in four hardwoods below fiber saturation point with magnetic resonance microimaging[J]. Wood Sci and Technol, 2015(49-6): 1251-1218.
[26]	FREDRIKSSON, MARIA, THYAESEN, et al. The states of water in norway spruce (picea abies (l.) karst.) studied by low field nuclear magnetic resonance (LFNMR) relaxometry: Assignment of free water populations based on quantitative wood anatomy[J]. Holzforschung 2017, 71(1): 77-90. doi: 10.1515/hf-2016-0044
[27]	ZHOU F, FU Z Y, ZHOU Y D, et al. Moisture transfer and stress development during high temperature drying of Chinese fir[J]. Dry Technol, 2019, 38(4): 545-554. doi: 10.1080/07373937.2019.1588900
[28]	XU K, YUAN S F, GAO Y L, et al. Characterization of moisture states and transport in MUF resin-impregnated poplar wood using low field nuclear magnetic resonance[J]. Dry Technol, 2020, 39(6): 1-12 doi: 10.1080/07373937.2021.1860312
[29]	JIN Q, ZHU L, HU D, et al. Nuclear magnetic resonance analysis of water absorption characteristics and dynamic changes in pore size distribution of wood-plastic composites[J]. BioResources, 2021, 16(2): 4064-4080. doi: 10.15376/biores
[30]	GAO J S, WANG X, TONG J W, et al. Large size translucent wood fiber reinforced PMMA porous composites with excellent thermal, acoustic and energy absorption properties[J]. Compos Commun, 2022, 30(12):101059 doi: 10.1016/j.coco.2022.101059
[31]	PROVENCHER S W. A constrained regularization method for inverting data represented by linear algebraic or integral equations[J]. Comput Phys Commun, 1982, 27(3): 213-227. doi: 10.1016/0010-4655(82)90173-4
[32]	曹金珍. 木材保护与改性[M]. 北京: 中国林业出版社, 2018.
[33]	WANG X A, ZHU W, DING K L, et al. Preliminary study on the preparation of poplar plastic woodII. Preparation of Poplar Esterified Plywood[J]. Journal of Northwest Forestry University, 2001, (03): 61-63.
	王新爱, 朱玮, 丁克廉, 等. 杨木塑合木制备初探—II. 杨木酯化塑合木的制备[J]. 西北林学院学报, 2001, (03): 61-63.
[34]	LI C F, WANG Q W, LIU M L, et al. Effect of preparation process on dimensional stability of larch plywood[J]. China Forest Products Industry, 2015, 42(01): 43-46.
	李春风, 王清文, 刘明利, 等. 制备工艺对落叶松单板塑合木尺寸稳定性的影响[J]. 林产工业, 2015, 42(01): 43-46.
[35]	ISLAM S, HAMDAN S, JUSON I, et al. The effect of alkali pretreatment on mechanical and morphological properties of tropical wood polymer composites[J]. Mater Design, 2012, 33(1): 419-424. doi: 10.1016/j.matdes.2011.04.044
[36]	WU J M WUY, HUANG Q T, et al. Effect of silane coupling agent modification on properties of transparent wood[J]. China Forest Products Industry, 2019, 46 (08): 22-25 + 29.
	吴佳敏, 吴燕, 黄琼涛, 等. 硅烷偶联剂改性对透明木材性能的影响[J]. 林产工业, 2019, 46(08): 22-25+29.
[37]	GAO X, ZHUANG S Z. Bound water content in saturated wood cell wall determined by nuclear magnetic resonance spectroscopy[J]. Chinese J Magn Reson, 2015, 32(4): 671-676.
	高鑫, 庄寿增. 利用核磁共振测木材吸着水饱和含量[J]. 波谱学杂志, 2015, 32(4): 671-676.
[38]	李新宇. 利用时域核磁共振技术研究木材孔隙分布及水分运动[D]. 内蒙古农业大学, 2017.
[39]	LIN Y S, ZHANG M H, GUAN M J. Nuclear magnetic resonance analysis of moisture absorption of wood[J]. Journal of Forestry Engineering, 2016, 1(2): 5.
	刘源松, 张明辉, 关明杰. 木材吸湿水分变化的核磁共振分析[J]. 林业工程学报, 2016, 1(2):5.
[40]	BLOEMBERGEN N, PURCELL E M., POUND R V. Relaxation effects in nuclear magnetic resonance absorption[J]. Phys Rev, 1948, 73: 679-712. doi: 10.1103/PhysRev.73.679
[41]	LI C, ZHANG M H, YU J F. Determination of wood moisture content by NMR free induction decay curve[J]. Journal of Beijing Forestry University, 2012, 34(4): 142-145.
	李超, 张明辉, 于建芳. 利用核磁共振自由感应衰减曲线测定木材含水率[J]. 北京林业大学学报, 2012, 34(4): 142-145.
[42]	PASSARINI L, MALVEAU C, HERNANDEZ R E. Water state study of wood structure of four hardwoods below fiber saturation point with nuclear magnetic resonance[J]. Wood Fiber Sci, 2014, 46(4): 480-488.
[43]	THYGEAEN L G, ELDER T. Moisture in untreated, acetylated, and furfurylated norway spruce studied during drying using time domain NMR[J]. Wood Fiber Sci, 2009, 41(2): 194-200.
[44]	MICHALSKA-POZOGA I, SZCZEPANEK M. Analysis of particles’ size and degree of distribution of a wooden filler in wood-polymer composites[J]. Materials, 2021, 14(21): 6251. doi: 10.3390/ma14216251
[45]	ČREŠNAR K P, BEK M, LUXBACHER T, BRUNCKO M, et al. Insight into the surface properties of wood fiber-polymer composites[J]. Polymers-Basel, 2021, 13(10): 1535.

试件编号	吸湿率/%	T₂(1)/ms	T₂(2)/ms	峰面积A(1)	峰面积A(2)	总面积A(总)
PM#0	19.30	0.36	2.68	0.12	29.52	29.64
PM#6-25	13.23	0.30	2.49	0.23	24.21	24.44
PM#6-50	12.58	0.60	2.47	0.37	22.94	23.31
PM#6-100	8.74	0.20	1.96	0.37	21.37	21.74
PM#12-25	13.03	0.30	2.60	0.22	23.46	23.68
PM#12-50	9.90	-	2.21	-	22.44	22.44
PM#12-100	7.42	0.20	1.95	0.31	18.60	18.91
PM#24-25	13.53	-	2.60	-	24.58	24.58
PM#24-50	9.51	-	1.85	-	17.82	17.82
PM#24-100	6.07	-	1.82	-	17.26	17.26

试件编号	吸水率/%	T₂(2)/ms	T₂(3)/ms	峰面积A(2)	峰面积A(3)	总面积A(总)
PM#0	130.73	4.50	102.34	69.90	13389.10	13459.60
PM#6-25	96.68	3.65	89.09	56.75	10254.02	10310.77
PM#6-50	81.65	3.40	89.07	58.44	8295.25	8353.69
PM#6-100	34.48	2.76	33.70	47.73	4237.27	4280.99
PM#12-25	89.35	3.41	89.07	45.92	7672.14	7718.06
PM#12-50	59.67	3.40	155.52	50.78	5154.88	5205.66
PM#12-100	31.70	2.96	77.53	51.60	2316.82	2368.42
PM#24-25	90.03	3.65	135.10	50.51	7688.59	7739.10
PM#24-50	47.81	2.58	64.47	32.74	5035.80	5068.54
PM#24-100	20.79	2.40	31.14	38.36	2098.09	2136.45