Cellulose (2019) 26:1995–2012
2009
Table 4 Average tensile properties and 95% confidence intervals of the BSKP sheets
Untreated BSKP restrained
Untreated BSKP unrestrained
HC BSKP restrained
HCBSKP unrestrained
HC ? LC BSKP unrestrained
Untreated BSKP, starch, CMF restrained
Untreated BSKP,
Untreated BSKP 6.7 kPa wet pressing unrestrained
starch, CMF unrestrained
Tensile
1.65 ± 0.04 1.05 ± 0.06 2.11 ± 0.02 1.90 ± 0.74 3.54 ± 0.15 2.53 ± 0.10 2.36 ± 0.28 1.42 ± 0.08
strength (kN/m)
Tensile
13.6 ± 0.5 6.4 ± 0.2 19.0 ± 0.2 15.6 ± 0.6 30.0 ± 1.8 21.0 ± 0.8 17.5 ± 2.1 12.3 ± 0.7
strength (MPa)
Tensile index
25.2 ± 0.9 15.2 ± 0.5 33.2 ± 0.4 27.5 ± 1.1 53.1 ± 2.3 40.6 ± 1.5 37.2 ± 4.2 24.6 ± 1.4
(Nm/g)
Tensile
270 ± 30 140 ± 40 289 ± 9
147 ± 16 129 ± 6
244 ± 19 137 ± 7.0 140 ± 6
stiffness (kN/m)
2.21 ± 0.11 0.86 ± 0.04 2.60 ± 0.08 1.21 ± 0.13 1.09 ± 0.03 2.03 ± 0.16 1.02 ± 0.05 1.21 ± 0.06
Tensile
modulus (GPa)
Strain at
2.12 ± 0.18 3.02 ± 0.18 4.31 ± 0.18 7.78 ± 0.21 9.25 ± 0.26 3.65 ± 0.30 6.2 ± 1.1 4.76 ± 0.18
break (%)
Work to break (mJ)
39.5 ± 4.8 35.7 ± 3.1 103.6 ± 5.1 157.7 ± 8.9 291 ± 24 94.3 ± 9.3 154 ± 34 71.4 ± 5.2
Tensile test repeats
10
10
10
10
5
10
10
10
Sample
121
163
111
122
118
120
135
115
thickness ( l m)
Sample width (mm)
15
15
15
15
15
15
15
15
Grammage (g/m 2 )
65.5
68.9
63.6
69.1
66.6
62.2
63.3
57.5
Density
541
423
573
566
564
518
469
500
(kg/m 3 )
Cross
1.82
2.45
1.67
1.83
1.77
1.80
2.03
1.73
section area (mm 2 )
2.57 ± 0.09 1.55 ± 0.05 3.38 ± 0.04 2.81 ± 0.11 5.42 ± 0.33 4.14 ± 0.16 3.80 ± 0.45 2.51 ± 0.14
Breaking length (km a )
a Breaking length values were reported in order to have improved comparability to classical articles related to individual pulp fibers
scale deformations caused by mechanical treatment (refining) on tensile behavior. The measured strength and elongation of individual BSKP fibers ranged from 200 to 1100 MPa, and from 8 to 32%, respectively. Only a few of the individual BSKP fiber tensile curves were apparently linear.
More often the slope of the stress strain-curves increased with straining which behavior could be related to the straightening of disordered regions in the fiber wall. None of the individual BSKP fiber tensile curves was similar to the typical concave downward shape of paper sheet.
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