Diapositiva 1 - Institute of Advanced Chemistry of Catalonia

aMahomed
Ussman, bDaniel López-Santana, bJosep Carilla and bAlbert M. Manich
aUniversidade da Beira Interior (UBI), Covilhã, Portugal
bInstitute of Advanced Chemistry of Catalonia (IQAC-CSIC), Barcelona, Spain
INTRODUCTION
INTRODUCTION
EXPERIMENTAL PART
PART
EXPERIMENTAL
Understanding the mechanism of Understanding the mechanism of FIBRES and
and TREATMENTS:
TREATMENTS:
FIBRES
water sorption and desorption of water sorption and desorption of UNTREATED FIBRES:
cellulosic fibres (1, 2) and how it is cellulosic fibres (1, 2) and how it is •PT04 CABUYA
modified by processing will provide •PT05 SISAL
modified by processing will provide a useful tools to exploit their a useful tools to exploit their •PT08 JUTE
properties according to the final •PT09 KENAF
properties according to the final •PT10 LUFFA
application. Sorption/desorption Sorption/desorption application.
HEMP AND FLAX RETTED FIBRES:
behaviour has been characterized behaviour has been characterized •PT11 LONG HEMP DEW RETTED LHDR
using a Dynamic Vapour Sorption using a Dynamic Vapour Sorption •PT12 LONG FLAX DEW RETTED LFDR
apparatus. The classical GAB model apparatus. The classical GAB model •PT13 SHORT FLAX DEW RETTED SFDR
has been used to analyze variations •PT14 SHORT HEMP DEW RETTD SHDR
has been used to analyze variations in monolayer and multilayer in monolayer and multilayer •PT15 LONG FLAX WATER RETTED LFWR
sorption (3), maximum sorption •PT16 COTTONIZED FLAX DEW Rd CFDR
sorption (3), maximum sorption FLAX RETTED AND SCOURED FIBRES:
capacity and hysteresis. Sorption capacity and hysteresis. Sorption •PT12Tr LFDRTr
parameters, water retention and parameters, water retention and •PT13Tr SFDRTr
crystallinity have been related to crystallinity have been related to identify the effect of fibre type and •PT15Tr LFWRTr
identify the effect of fibre type and •PT16Tr CFDRTr
treatments (retting, scouring) on treatments (retting, scouring) on •PL01 POLISH FLAX FABRIC PLUT
the evolution of the results.
the evolution of the results.
•PL02 POLISH FLAX FAB. ENZIM’Tr PLET
CRYSTALLINITY (XRD)
(XRD) KR
KR
CRYSTALLINITY
Crys‐ Water PEK model Sorp/Desorp 5‐95%
Barrier effect
Vapour molecules
Cabuya
Sisal Juta Kenaf Luffa
LHDR LFDR SFDR SHDR LFWR CFDR LFDRTr
SFDRTr
LFWRTr
CFDRTr
PUT PET nity tion Sfast Sslow Dfast Dslow Xm
C
K
X1
57.0 111.7 14.28 10.27 13.20 9.59 6.27 10.96 0.818 34.05 32.85
50.0 99.5 12.64 20.66 23.55 7.94 4.65 16.54 0.921 58.41 25.89
65.0 62.1 14.68 8.32 13.50 8.72 6.49 9.04 0.801 31.86 32.08
73.0 97.9 14.97 8.69 14.80 8.28 6.57 8.12 0.801 32.11 26.97
62.0 200.5 14.58 8.44 13.48 8.79 6.84 8.66 0.786 31.18 32.57
74.0 75.7 7.94 14.25 14.21 6.65 5.46 17.02 0.817 29.56 28.53
80.0 68.6 8.52 11.49 14.00 5.08 4.86 16.53 0.820 26.73 21.19
76.0 75.0 8.53 11.03 13.51 5.15 4.91 16.66 0.812 25.96 22.23
77.0 74.1 8.20 13.22 14.74 5.66 4.69 21.97 0.844 29.97 26.84
78.3 71.9 9.04 11.14 13.62 5.36 4.74 15.01 0.825 26.86 21.19
82.0 65.2 8.24 10.70 13.06 5.04 4.89 15.25 0.809 25.30 23.28
86.6 58.4 9.32 9.43 11.92 5.89 4.73 12.59 0.812 24.87 21.78
86.0 59.0 9.39 8.91 12.18 5.38 4.82 11.82 0.804 24.12 20.36
89.7 53.8 8.43 9.42 11.75 5.31 4.61 11.03 0.808 23.57 20.95
88.2 53.9 10.23 7.41 12.36 4.75 5.12 9.23 0.760 23.46 20.68
91.8 50.5 7.35 9.04 10.51 4.86 4.59 14.62 0.787 21.22 22.23
92.5 49.6 6.99 9.40 10.25 5.11 4.55 14.33 0.788 21.19 25.45
Sorbed molecules
Sorption and desorption is a gradual process in dynamic equilibrium (5).
Sorption sites
Polymer chain
Sorption and desorption kinetics can be modelled considering two
processes in parallell: a) fast sorption that easily reach locations 1 and 2, and b) slow sorption that hardly reach locations 3 and 4:
Q5000SA Dynamic Vapour Sorption DVS Analyser from TA Instruments.
PEK Model: S(t) = Sfast*[1‐EXP(‐t/Tfast)]+Sslow*[1‐EXP(‐t/Tslow)]
The total amount Sorbed/Desorbed can be split in two: the sorbed in easily accesible sites (Sfast) and in the hardly accesible sites (Sslow).
GAB model: Parameters estimated at desorption isothermal process
Hyste‐
resis
35‐65%
GAB model
DIRECT SORP
SORPTION SITES a: Crystalline region, b: Amorphous region, c: interfibrilar
molecules, d: internal pores. SORBED WATER LOCATION 1: External, 2: Amorphous region, 3: Internal, 4: Crystalline region (4)
RESULTS
RESULTS
Description talli‐ Reten‐
INDIRECT SORP
WATER RETENTION
RETENTION VALUE
VALUE WR
WR
WATER
X = Xm C K aw / [(1 – K aw) (1 – K aw + C K aw)]
aw
X
Water activity expressed as vapour relative pressure p/p0, where p0 is the pressure of saturated vapour. It can be expressed as relative humidity RH (%) = 100×aw
Equilibrium moisture content at aw in g sorbed/ 100 g of sorbent on dry basis
Xm
Monolayer moisture content in g sorbed/ 100 g of sorbent on dry basis C
Monolayer constant. Proportional to the rate between both the attachment and the escape rate constants of the primary sites.
Multilayer constant. Proportional to the rate between the attachment rate constant and the escape for all higher layers.
K
X1
Maximum moisture content (sorption capacity) at aw=1 (100% Relative Humidity)
Hysteresis
(%)
FACTORIAL ANALYSIS
ANALYSIS
FACTORIAL
Xdes‐Xsorp
Xsorp
Sslow
K Dfast
X1
C
Dslow
Water Retention
Hysteresis
Sfast
Xm
Crystallinity
-0.8 -0.6 -0.4 -0.2
0
0.2
0.4
0.6
0.8
1
1st Factor - Primary sorption (monolayer)
Cellulosic Samples
16
Sisal
14
12
10
Untreated
HEMP
8
Retted
6
SHDR
4
LHDR
Cabuya
2 LFDR
LFWR
0 CFDR
SFDR
Kenaf
Jute
LFDRtr
Luffa
-2 LFWRtr
SFDRtr
Scoured
-4
PLUT PLET CFDRtr
Scoured
-6
FLAX
-6
-4
-2
0
2
4
6
8
10
12
1st Factor - Primary sorption (monolayer)
FLAX & HEMP (Retted, Scoured)
94
Crystallinity / %
FACTORIAL ANALYSIS
1
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
2nd F - Multilayer sorp.
2nd. F - Multilayer sorp.
The Factorial Analysis of the responses enabled us to group them
into two main variables that identify the main factors that make
different the samples. They can be classified into similar groups (6).
Cryst = 124.2 - 0.65* Water Ret
r = -0.996
90
86
82
78
74
49
54
59
64
69
74
79
Water retention / %
Cellulosic fibres can be identified by two factors: 1st) The primary sorption that decreases with crystallinity and increases with the extent of the monolayer, the water retention, the fast sorption, the slow desorption and consequently the hysteresis, and 2nd) the secondary (multilayer) sorption that decreases with crystallinity and increases with the maximum sorption capacity, the multilayer constant, the slow sorption and the fast desorption. Based on Water Retention, Crystallinity of the Retted Flax and Hemp fibres can be estimated by regression.
CONCLUSIONS
CONCLUSIONS
•Factorial Analysis: Water Sorption and retention of Cellulosic Fibres are ruled by two independent factors that depends on primary and secondary sorption.
•Factorial Analysis: Water Sorption and retention of Cellulosic Fibres are ruled by two independent factors that depends on primary and secondary sorption.
•The application of the Parallel Exponential Model enabled us to split sorption and desorption in two complementary fast and slow processes.
processes.
•The application of the Parallel Exponential Model enabled us to split sorption and desorption in two complementary fast and slow
•Retting and Scouring increases Crystallinity of Cellulosic Fibres at the expense of removing non‐cellulosic components and amorphous cellulose regions.
•Retting and Scouring increases Crystallinity of Cellulosic Fibres at the expense of removing non‐cellulosic components and amorphous cellulose regions.
•For flax and hemp retted fibres crystallinity can be estimated from water retention due to the very highly significant linear regression.
•For flax and hemp retted fibres crystallinity can be estimated from water retention due to the very highly significant linear regression.
ACKNOWLEGEMENTS : The
: Theauthors
authorsare
areindebted
indebtedto the
to theSabbatical
SabbaticalGrant
Grant(BSAB) given
(BSAB) givento Prof. Ussman by
to Prof. Ussman bythe
the“Fundaçao
“Fundaçaopara a Ciência
para a Ciênciae a Tecnologia”
e a Tecnologia”FCT of MCTES (Portugal) and to MAT2010‐20324‐CO2‐02 Spanish
FCT of MCTES (Portugal) and to MAT2010‐20324‐CO2‐02 SpanishProject.
Project.
ACKNOWLEGEMENTS
1. S. Okubayashi, U.J. Griesser, T. Bechtold, J Appl Polym Sci 97, (2005), 1621‐1625
2. R. Kohler, R. Dück, B Ausperger, R. Alex, Composite Interfaces, 10, 2‐3 (2003) 255‐276
3. E.O. Timmermann, Colloids and Surf.A: Physicochem. Eng. Aspects 220 (2003), 235‐260.
4. S. Okubayashi, U.J. Griesser, T. Bechtold, Carbohydrate Polym 58 (2004) 293‐299
5. A.M. Manich, F. Maldonado, J. Carilla, M. Catalina, A. Marsal, J Am Leath Chem Ass 105 (2010) 229‐241
6. P. Dagnelie “Analyse statistique à plusieurs variables”, Les Presses Agron. Gembloux, 1986, pp.191‐224
m_ussman@ubi.pt
albert.manich@iqac.csic.es