Characterization of moisture in acetylated and propionylated radiata pine using low-field nuclear magnetic resonance (LFNMR) relaxometry

被引:53
作者
Beck, Greeley [1 ,2 ]
Thybring, Emil Engelund [3 ]
Thygesen, Lisbeth Garbrecht [3 ]
Hill, Callum [4 ]
机构
[1] Norwegian Inst Bioecon Res NIBIO, Forest & Forest Resources, POB 115, NO-1431 As, Norway
[2] Norwegian Univ Life Sci, Dept Nat Resources Management, POB 5003, NO-1432 As, Norway
[3] Univ Copenhagen, Dept Geosci & Nat Resource Management, Rolighedsvej 23, DK-1958 Frederiksberg C, Denmark
[4] Norwegian Inst Bioecon Res NIBIO, POB 115, NO-1431 As, Norway
关键词
acetylation; cryo-relaxometry; fiber saturation point (FSP); low-field nuclear magnetic resonance (LFNMR); modified wood; moisture content; propionylation; spin-spin relaxation time (T-2); CARBOXYLIC-ACID ANHYDRIDES; ROT DECAY RESISTANCE; NMR RELAXATION; MODIFIED WOOD; WATER DISTRIBUTION; BOUND WATER; SORPTION;
D O I
10.1515/hf-2017-0072
中图分类号
S7 [林业];
学科分类号
0829 ; 0907 ;
摘要
Moisture in radiata pine (Pinus radiata D. Don) earlywood (EW), which was acetylated or propionylated to various degrees, was measured by low-field nuclear magnetic resonance (LFNMR) relaxometry. Spin-spin relaxation times (T-2) were determined for fully saturated samples at 22 and -18 degrees C. T-2 values for EW lumen water increased with increasing acetylation weight percentage gain (WPG), perhaps caused by the less hydrophilic acetylated wood (AcW) surface. Cell wall water (W-CW) and the water in pits and small voids also showed increasing T-2 values as a function of WPG but with a weaker tendency. A possible explanation is the counteracting effects of decreased hydrophilicity and reduced moisture content (MC) of these water populations at higher levels of acetylation. The evaluation of propionylation on W-CW T-2 data was complicated by peak splitting in the relaxation spectrum. Constant T-2 values for void water populations at various WPG levels for propionylated samples indicate a modification gradient in the cell wall. Fiber saturation point (FSP) was significantly reduced by both modifications. Slightly higher FSP values for propionylated samples suggest that physical bulking is not the only factor causing moisture exclusion in AcW. But this interpretation is tentative because of the possibility of cell wall damage caused by propionylation.
引用
收藏
页码:225 / 233
页数:9
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