Figure 4.5
0
4
8
12
16
130
q BNC
E ligament
E
q ligament
0
2.5
5
7.5
10
336
Swelling Degree, q
Tensile Modulus, E [MPa]
0
1
2
3
4
40
q BNC
ε BNC
ε ligament
σ ligament
0
0.3
0.6
0.9
1.2
1.5
1.8
Tensile Fracture Stress, σ
F [MPa]
Tensile Fracture Strain,
ε
F [mm/mm]
1
2
3
4
0
1
2
3
4
5
AAm Concentration [M]
AAm Concentration [M]
(a)
(b)
80
Bacterial Cellulose
Figure 4.5
Effect.of.AAm.concentration.on.the.tensile.strength.performance.of.BNC-PAAm.gel.under.the.
conditions.of.0.1.mol%.MBAA.and.0.1.mol%.KPS:.(a).swelling.degree,.q,.and.tensile.modulus,.
E,. as. functions. of. the. concentration. of. AAm. (M). in. the. BNC-PAAm. gel.. (b). Tensile. fracture.
stress,.σ F ,.and.tensile.fracture.strain,.ε F ,.as.functions.of.the.concentration.of.AAm.(M).in.the.
BNC-PAAm.gel..The.symbols.are.as.follows:.(a).(●).q BNC-PAAm ;.(■).q BNC ,.(▲).q ligament ;.(○).E BNC-AAm ;.
(□) E BNC ,. ( ). E ligament ;. (b). (●). σ F BNC-PAAm;. (■). σ F BNC;. (▲). σ F . ligament;. (○). ε F BNC-PAAm;.
(□) ε F BNC;.( ).ε F .ligament..(Reproduced.with.permission.of.Hagiwara.et.al..2010.)
decreased.with.increasing.AAm.concentration.and.was.more.than.10.times.
greater.than.that.of.ligament.(ε F .=.0.17.m/m)..The.tendency.for.the.compressive.strength.was.similar.to.that.of.the.tensile.strength.for.the.BNC-PAAm.
DN.gel.(Hagiwara.et.al..2010)..These.results.indicate.that.the.concentration.
of. AAm. affected. the. mechanical. performance. in. terms. of. both. the. tensile.
and.compressive.strengths..A.higher.concentration.of.AAm.(4.M).led.to.high.
. tensile.and.compressive.strength.of.the.BNC-PAAm.DN.gels.
Effect of Cross-Linking
Since.the.mechanical.properties.of.the.gel.also.depend.on.the.cross-linker.
concentration.of.the.second.network,.the.effect.of.the.degree.of.cross-linking.on.the.tensile.and.compressive.strength.was.investigated.by.changing.
the. N,N′-methylenebis. acrylamide. (MBAA). concentration. while. keeping.
the.in-feed.AAm.concentration.constant.at.4.M..The.concentration.of.potassium. peroxydisulfate. (K 2 S 2 O 8 ). (KPS). was. also. kept. constant. at. 0.1. mol%..
Figure 4.6. shows. the. effect. of. MBAA. concentration. on. the. tensile. properties.of.BNC-PAAm.DN.gel..Tensile.moduli.of.BNC-PAAm.DN.gel.increased.
with.increasing.MBAA.concentration.(Figure 4.6a)..Meanwhile,.as.shown.in.
Figure 4.6b,.a.drastic.increase.in.the.tensile.fracture.stress.of.the.BNC-PAAm.
DN.gel.was.observed.for.MBAA.concentrations.below.1.mol%..In.contrast,.
the. tensile. fracture. strain. of. the. BNC-PAAm. gels. drastically. decreased. up.
to. an. MBAA. concentration. of. 1. mol%.. Above. 1. mol%. MBAA. concentration,.there.was.no.significant.improvement.of.either. tensile.fracture.stress.
or.strain..This.indicates.that.1.mol%.was.an.effective.MBAA.concentration.
0
4
8
12
16
130
q BNC
E ligament
E
q ligament
0
2.5
5
7.5
10
336
Swelling Degree, q
Tensile Modulus, E [MPa]
0
1
2
3
4
40
q BNC
ε BNC
ε ligament
σ ligament
0
0.3
0.6
0.9
1.2
1.5
1.8
Tensile Fracture Stress, σ
F [MPa]
Tensile Fracture Strain,
ε
F [mm/mm]
1
2
3
4
0
1
2
3
4
5
AAm Concentration [M]
AAm Concentration [M]
(a)
(b)
80
Bacterial Cellulose
Figure 4.5
Effect.of.AAm.concentration.on.the.tensile.strength.performance.of.BNC-PAAm.gel.under.the.
conditions.of.0.1.mol%.MBAA.and.0.1.mol%.KPS:.(a).swelling.degree,.q,.and.tensile.modulus,.
E,. as. functions. of. the. concentration. of. AAm. (M). in. the. BNC-PAAm. gel.. (b). Tensile. fracture.
stress,.σ F ,.and.tensile.fracture.strain,.ε F ,.as.functions.of.the.concentration.of.AAm.(M).in.the.
BNC-PAAm.gel..The.symbols.are.as.follows:.(a).(●).q BNC-PAAm ;.(■).q BNC ,.(▲).q ligament ;.(○).E BNC-AAm ;.
(□) E BNC ,. ( ). E ligament ;. (b). (●). σ F BNC-PAAm;. (■). σ F BNC;. (▲). σ F . ligament;. (○). ε F BNC-PAAm;.
(□) ε F BNC;.( ).ε F .ligament..(Reproduced.with.permission.of.Hagiwara.et.al..2010.)
decreased.with.increasing.AAm.concentration.and.was.more.than.10.times.
greater.than.that.of.ligament.(ε F .=.0.17.m/m)..The.tendency.for.the.compressive.strength.was.similar.to.that.of.the.tensile.strength.for.the.BNC-PAAm.
DN.gel.(Hagiwara.et.al..2010)..These.results.indicate.that.the.concentration.
of. AAm. affected. the. mechanical. performance. in. terms. of. both. the. tensile.
and.compressive.strengths..A.higher.concentration.of.AAm.(4.M).led.to.high.
. tensile.and.compressive.strength.of.the.BNC-PAAm.DN.gels.
Effect of Cross-Linking
Since.the.mechanical.properties.of.the.gel.also.depend.on.the.cross-linker.
concentration.of.the.second.network,.the.effect.of.the.degree.of.cross-linking.on.the.tensile.and.compressive.strength.was.investigated.by.changing.
the. N,N′-methylenebis. acrylamide. (MBAA). concentration. while. keeping.
the.in-feed.AAm.concentration.constant.at.4.M..The.concentration.of.potassium. peroxydisulfate. (K 2 S 2 O 8 ). (KPS). was. also. kept. constant. at. 0.1. mol%..
Figure 4.6. shows. the. effect. of. MBAA. concentration. on. the. tensile. properties.of.BNC-PAAm.DN.gel..Tensile.moduli.of.BNC-PAAm.DN.gel.increased.
with.increasing.MBAA.concentration.(Figure 4.6a)..Meanwhile,.as.shown.in.
Figure 4.6b,.a.drastic.increase.in.the.tensile.fracture.stress.of.the.BNC-PAAm.
DN.gel.was.observed.for.MBAA.concentrations.below.1.mol%..In.contrast,.
the. tensile. fracture. strain. of. the. BNC-PAAm. gels. drastically. decreased. up.
to. an. MBAA. concentration. of. 1. mol%.. Above. 1. mol%. MBAA. concentration,.there.was.no.significant.improvement.of.either. tensile.fracture.stress.
or.strain..This.indicates.that.1.mol%.was.an.effective.MBAA.concentration.