Accelerated wet aging study of flax-reinforced UPR composites
The plain and satin fabrics were weaved with 66.67 tex flax yarns. With flax fabric as the reinforcement and Unsaturated Polyester Resin (UPR) as the matrix, composites of two, three and four layers were fabricated respectively by the Vacuum Assisted Resin Infusion (VARI) technique. The wetting capa...
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| Cite this: | Accelerated wet aging study of flax-reinforced UPR composites / Wang Qiuhong, Ji Yingchao, Wang Ying, Li Hong // Functional Materials. — 2016. — Т. 23, № 1. — С. 120-126. — Бібліогр.: 24 назв. — англ. |
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nasplib_isofts_kiev_ua-123456789-1205632025-02-09T14:02:22Z Accelerated wet aging study of flax-reinforced UPR composites Дослідження пришвидшеного вологого старіння композитів НПС, зміцнених льоном Wang Qiuhong Ji Yingchao Wang Ying Li Hong Technology The plain and satin fabrics were weaved with 66.67 tex flax yarns. With flax fabric as the reinforcement and Unsaturated Polyester Resin (UPR) as the matrix, composites of two, three and four layers were fabricated respectively by the Vacuum Assisted Resin Infusion (VARI) technique. The wetting capability of the composites was tested firstly. The wetting rate illustrated that the weight of the composites were fast increased when immersed in the water. And the impact property of the composites after saturated in the water for different duration time was tested. The impact property of the four-layer plain fabrics composites was decreased after immersing in water for one-, two-and three-month. After reaching the minimum impact property, the impact property was found recovered after six-month water immersion. For the two- and three-layer plain fabrics specimens, the impact property was increased in the whole experiment process. For the two-layer satin fabrics specimens, the impact property was increased initially for one-month, decreased for two-month and three-month and increased instead for six-month after water immersion. Scanning electron microscopy (SEM) confirmed that the enhancement effect of the wet flax fibre may be over-weighed by the degradation effect of the materials. The results indicated that the materials had experienced some forms of physical damage and/or chemical degradation. The weakening of bonding between fibre and matrix and softening of matrix material were also reasons of the decreased composite property. This work supported by Fund of Project of Education Department of Liaoning Province, China (No.2006B013). Liaoning province colleges’ outstanding talent support program (No. LJQ2015008). 2016 Article Accelerated wet aging study of flax-reinforced UPR composites / Wang Qiuhong, Ji Yingchao, Wang Ying, Li Hong // Functional Materials. — 2016. — Т. 23, № 1. — С. 120-126. — Бібліогр.: 24 назв. — англ. 1027-5495 DOI: http://dx.doi.org/10.15407/fm23.01.120 https://nasplib.isofts.kiev.ua/handle/123456789/120563 en Functional Materials application/pdf НТК «Інститут монокристалів» НАН України |
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Technology Technology Wang Qiuhong Ji Yingchao Wang Ying Li Hong Accelerated wet aging study of flax-reinforced UPR composites Functional Materials |
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The plain and satin fabrics were weaved with 66.67 tex flax yarns. With flax fabric as the reinforcement and Unsaturated Polyester Resin (UPR) as the matrix, composites of two, three and four layers were fabricated respectively by the Vacuum Assisted Resin Infusion (VARI) technique. The wetting capability of the composites was tested firstly. The wetting rate illustrated that the weight of the composites were fast increased when immersed in the water. And the impact property of the composites after saturated in the water for different duration time was tested. The impact property of the four-layer plain fabrics composites was decreased after immersing in water for one-, two-and three-month. After reaching the minimum impact property, the impact property was found recovered after six-month water immersion. For the two- and three-layer plain fabrics specimens, the impact property was increased in the whole experiment process. For the two-layer satin fabrics specimens, the impact property was increased initially for one-month, decreased for two-month and three-month and increased instead for six-month after water immersion. Scanning electron microscopy (SEM) confirmed that the enhancement effect of the wet flax fibre may be over-weighed by the degradation effect of the materials. The results indicated that the materials had experienced some forms of physical damage and/or chemical degradation. The weakening of bonding between fibre and matrix and softening of matrix material were also reasons of the decreased composite property. |
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Wang Qiuhong Ji Yingchao Wang Ying Li Hong |
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Wang Qiuhong Ji Yingchao Wang Ying Li Hong |
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Wang Qiuhong |
| title |
Accelerated wet aging study of flax-reinforced UPR composites |
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Accelerated wet aging study of flax-reinforced UPR composites |
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Accelerated wet aging study of flax-reinforced UPR composites |
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Accelerated wet aging study of flax-reinforced UPR composites |
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Accelerated wet aging study of flax-reinforced UPR composites |
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accelerated wet aging study of flax-reinforced upr composites |
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НТК «Інститут монокристалів» НАН України |
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Accelerated wet aging study of flax-reinforced UPR composites / Wang Qiuhong, Ji Yingchao, Wang Ying, Li Hong // Functional Materials. — 2016. — Т. 23, № 1. — С. 120-126. — Бібліогр.: 24 назв. — англ. |
| series |
Functional Materials |
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| fulltext |
120 Functional materials, 23, 1, 2016
ISSN 1027-5495. Functional Materials, 23, No.1 (2016), p. 120-126
doi:http://dx.doi.org/10.15407/fm23.01.120 © 2016 — STC “Institute for Single Crystals”
Accelerated wet aging study
of flax-reinforced UPR composites
Wang Qiuhong, Ji Yingchao, Wang Ying, Li Hong
School of Textile and Material Engineering, Dalian Polytechnic University,
Dalian, Liaoning, 116034, P.R. China
Received 27 July, 2015
The plain and satin fabrics were weaved with 66.67 tex flax yarns. With flax fabric as the
reinforcement and Unsaturated Polyester Resin (UPR) as the matrix, composites of two, three
and four layers were fabricated respectively by the Vacuum Assisted Resin Infusion (VARI)
technique. The wetting capability of the composites was tested firstly. The wetting rate illus-
trated that the weight of the composites were fast increased when immersed in the water. And
the impact property of the composites after saturated in the water for different duration time
was tested. The impact property of the four-layer plain fabrics composites was decreased af-
ter immersing in water for one-, two-and three-month. After reaching the minimum impact
property, the impact property was found recovered after six-month water immersion. For the
two- and three-layer plain fabrics specimens, the impact property was increased in the whole
experiment process. For the two-layer satin fabrics specimens, the impact property was in-
creased initially for one-month, decreased for two-month and three-month and increased in-
stead for six-month after water immersion. Scanning electron microscopy (SEM) confirmed
that the enhancement effect of the wet flax fibre may be over-weighed by the degradation ef-
fect of the materials. The results indicated that the materials had experienced some forms of
physical damage and/or chemical degradation. The weakening of bonding between fibre and
matrix and softening of matrix material were also reasons of the decreased composite property.
Keywords: Flax/UPR composites, wet aging, impact property.
Получены композиты из двух, трех и четырех слоев обычных и атласных тканей сотка-
ных с льняными нитями 66.67 tex с помощью метода вакуумной инфузии смолы (VARI).
Вначале исследовали смачивание композитов. Скорость смачивания показала, что вес ком-
позитов увеличивался при погружении в воду. Затем испытали свойства композитов пос-
ле насыщения в воде в течение различного времени. У четырехслойных обычных тканей
свойства снижались после вымачивания в течение 1-3 месяцев. После достижения мини-
мума свойства восстанавливались через 6 месяцев вымачивания. Для двух- и трехслойных
обычных тканей свойства возрастали на протяжении всего эксперимента. Для двухслой-
ных атласных тканей возрастание было 1 месяц, 2 месяца – снижение и опять возрастание
после 6 месяцев. Сканирующая электронная микроскопия подтвердила, что упрочняющий
эффект влажных льняных волокон может уступать эффекту деградации материала. Резуль-
таты показали, что материалы подверглись физическим повреждениям и/или химической
деградации. Ослабление связи между волокном и матрицей и размягчение материала мат-
рицы также были причиной снижения свойств композитов.
Дослідження пришвидшеного вологого старіння композитів НПС, зміцнених
льоном. Ван Цюхун, Цзи Інчао, Ван Ін, Лі Хун
Отримані композити з двох, три і чотирьох шарів звичайних і атласних тканин сотканых
з льняними нитками 66.67 tex методом вакуумної інфузії смоли (VARI). Спочатку дослідили
змочення композитів. Швидкість змочування показала, що вага композитів збільшувалась
Functional materials, 23, 1, 2016 121
Wang Qiuhong et al. / Accelerated wet aging study ...
1. Introduction
In recent years environmental problem
has become one of the major concerns about
the composite research. The high performance
synthetic fibres such as glass, aramid, nylon
and carbon are expensive and non-renewable
although they are used extensively for the re-
inforcement of plastics. The disposal of the
abandoned composite materials has become one
sources of environmental pollution when these
high performance fibers are involved. Eco-
materials based on renewable resources have
attracted growing attention. In many parts of
the world, apart from agricultural uses, differ-
ent parts of the plants have been found to be
viable sources of raw materials for industrial
purposes [1].Natural fibres, as a relatively
new group of environmental friendly materials
and a substitute of glass fibre in the composite
components, have gained renewed interest
in the last decade, by unifying technological,
economic and ecological aspects [2,3]. Natural
short-fibre reinforced polymeric composites are
finding applications in many fields ranging from
construction industry to automotive industry.
The use of natural short fibre in composites has
increased due to their relative cheapness, their
ability to recycle and for the fact that they can
compete well in terms of strength per weight of
material. Over the past decade, cellulose fibres
of a fibrous nature have been of great impor-
tance, because they can improve the mechani-
cal properties of composites compared to those
containing non-fibrous fibres [4-10].
Despite the attractiveness of natural fiber
reinforced polymer matrix composites, the
disadvantages are moisture absorption leading
to fibre swelling and local or seasonal variations
in quality that prevent wider use of the compos-
ites. The possibility for the outdoor applications
makes it necessary to analyze their mechani-
cal behavior under the influence of weather-
ing, which is not a well-studied area. Exequiel
Rodriguez et al. have reported that glass fibre
composite absorbed ten times less than the jute,
sisal and flax composites. Moisture absorption
studies of sisal fibre reinforced polypropylene
composites have been reported by C. P. L.Chow
et al. It has been concluded that the mechanical
strength decreased continuously by hot water
immersion treatment. Rouison D. et al. studied
water absorption of hemp fiber/unsaturated
polyester composites and found composite
samples immersed in water reached saturation
levels after about eight months and showed no
signs of cracking due to swelling [11-13].
The flax plant is a member of the Lina-
ceae family which is important for the pro-
duction of low density fibre. Different variet-
ies of flax are grown in Netherland, Belgium,
France and North China. Flax is one of the
major natural materials with great potential
application in the composite field. Compared
with the high performance fibers, such as
Kevlar, carbon and glass, the main flax fiber
has much higher moisture absorption ability
because of its chemical composition and mo-
lecular structure. Questions have been raised
regarding the property of the flax reinforced
materials after long time exposure to high
humidity environment. The effect of moisture
on the composites is an important matter since
such environmental factors are often present
in actual service conditions. It is indispensable
that the composites retain their mechanical
properties with less degradation in the moisture
environments [14-17].
It is believed that in the humid environment,
water molecules will enter the interface of
the composites because of the capillarity [18-
19]. The polymer matrix and the fibre/matrix
interface can be degraded by a hydrolysis
reaction of unsaturated groups within the resin
[20-23]. Debonding may occur at fibre/matrix
interface [24]. A concern with using flax fibre
composites in high humidity conditions is the
limited understanding and small database of
information of their durability.
The aim of this study is to find out the
mechanical behavior of the flax/UPR composites
after long term water damage and compare
the impact property variation of different
composites. In this investigation, two-, three-
при зануренні у воду. Далі тестували властивості композитів після насичення у воді про-
тягом різного часу. У чотиришарових звичайних тканин властивості знижувались протя-
гом 1-3 місяців. Після досягнення мінімуму властивості відновлювались через 6 місяців
вимочування. Для дво- і тришарових звичайних тканин властивості зростали протягом
всього експерименту. Для двошарових атласних тканин зростання було 1 місяць, 2 міся-
ці – зниження, і знову зростання після 6 місяців. Сканувальна електронна мікроскопія
підтвердила, що зміцнювальний ефект вологих льняних волокон може поступатися
ефекту деградації матеріалу. Результати показали, що матеріали зазнали фізичних уш-
коджень та/або хімічної деградації. Послаблення зв’язку між волокном та матрицею та
розм’якшення матеріалу матриці також спричиняли зниження властивостей композитів.
122 Functional materials, 23, 1, 2016
Wang Qiuhong et al. / Accelerated wet aging study ...
and four-layer flax fabrics constructed by plain
and satin weave fabricated with unsaturated
polyester resin (UPR) by using the vacuum
associated resin infusion (VARI) technique
firstly. Moreover, the laminates were put into
a water tub. After different duration of soaking
time, the impact property of the samples was
tested. At last, SEM is used to investigate
the degradation mechanism of the flax/ UPR
composites after immersed in water for certain
period of time.
2. Experimental
2.1 Fabrics weaving
The flax yarns used in the experiments were
provided by the Jamusi Textile Company (Hei-
longjiang province, P. R. China). The yarn fine-
ness was 66.67 tex with the tensile strength of
944.8 cN and elongation at break of 1.48 %. The
fabric was woven on a rapier loom developed by
the Tianjin Polytechnic University. The plain
and satin fabrics were weaved with the warp
count of 100 ends/10cm and weft count of 100
picks/10cm. The plain fabric area weight was
127.95 g/m2 and thickness 0.59 mm. The satin
fabric area weight was 118.68 g/m2 and thick-
ness 0.75 mm. Figure (1) illustrated the fabric
structure.
2.2 Composites fabricating
Vacuum Assisted Resin Infusion (VARI)
technique was used to fabricate the two-, three-
and four-layer laminates, separately with the
size of 300 mm×300 mm. UPR 196 s was se-
lected as the matrix, which viscosity was 0.22-
0.44Pa·S at 25 °C and corresponding hard-
ener methyl ethyl ketone peroxide (MEKP) as
well as promoter cobalt naphthenate were in-
cluded in the ingredient. The percentage was
100×1.2×1.5 in weight. VARI technological pro-
cess is shown in Fig. (2).
2.3 Wetting rate testing of the compos-
ites
According to the GB1034-86, laminates
were cut into the size of 20 mm×20 mm and im-
mersed in distilled water at room temperature.
The specimens were taken out from distilled
water, wiped and weighed. The wetting rate
was calculated using the following equation:
R
W W
W
=
-
´t 0
0
100% (1)
where, R – the wetting rate; W0 – the compos-
ite weight before wetting; Wt – the composite
weight after wetting.
2.4 Wet aging of the composites
According to the HB7401-1996, 48 hours after the
fabrication of composites, samples were divided into
five groups corresponding to different water immersion
periods. In the experiment, five time intervals were
used, i.e. 0, one, two, three and six months respectively.
The composite panels were immersed in a large tub
containing distilled water. The room temperature
during the experiment was within 25~30 °C. The
panels were withdrawn from the water at planned days,
wiped dry to remove the water on the surface. After
weighed, impact property was tested within 30 minutes
after the withdrawal of the samples from the tub.
2.5 Impact property testing of the com-
posites
Laminates were cut parts of 95 mm×95 mm
in accordance with ASTM D3763 rules. The
impact property was tested with the Universal
Impact Tester (INSTRON Dynatup 9250HV,
United States). The weight of impact hammer
was 5.7806 kg, form was bullet and speed was
2.5 m/s. For each group of composites, the val-
Fig. 1. Fabric structure
Fig. 2. VARI technological process, where,
1 – resin entrance; 2 – resin distribution (three
sections); 3 – skimmed film; 4 – rigid mold; 5 –
fabric; 6 – air tube (connecting vacuum pump);
7,8,9 – flexible molds.
Functional materials, 23, 1, 2016 123
Wang Qiuhong et al. / Accelerated wet aging study ...
ues of the impact property were the arithmetic
mean of at least eight specimens.
2.6 SEM Testing of the Composites
The broken sections of the flax/ UPR composite
before and after the water immersion were investigat-
ed by SEM (Quanta-2000, Czech).
3. Results and Discussion
3.1 Wetting capability of the composites
The wetting rate of different layer compos-
ites was shown in Fig. (3).
From Fig. (3), it can been seen that the wet-
ting rate of flax-reinforced UPR composites in-
creased fast during the prime 24 hours, with
2-layer specimens 3.23 %, 3-layer 2.98 % and
4-layer 3.11 %. From 1- day to 6-day, in spite
of the data fluctuating, the total trend of wet-
ting rate curve raises and reached to the maxi-
mum, i.e.2-layer 5.19 %, 3-layer 5.58 % and 4-
layer 6.2 % on 9-day in this experiment. The
reasons were as follows. Firstly, hydroxyl cova-
lent binding occured between water molecules
and flax fibre or resin matrix. And at the same
time, water molecules arised capillary infiltra-
tion along the inter-phase between fibre and
resin and the holes in materials. Moreover, the
weight of materials decreased owing to water
dissolution and degradation. Therefore, it was
obvious that the weight changes of the flax-re-
inforced UPR composites were affected by the
two aspects above.
3.2 Effect of impact property
The two-, three- and four-layers plain fab-
rics-reinforced UPR composites and two-layers
satin composites were immersed in distilled
water for one, two, three and six months respec-
tively. The impact properties were tested and
the results were shown in Fig. (4) and Fig. (5).
From Fig. (4) and Fig. (5), it can be seen that
the impact property of different composites was
different. The impact property of the two-layer
satin composites was decreased for two- and
three-month. The impact property of the four-
layer plain composites for one-, two- and three-
month was decreased obviously but recovered
for six-month. From the original specimens,the
impact property of the four-layer composites
was the best. The decline of the impact prop-
erty of the composites obtained in this experi-
ment may be a consequence of the different in-
fluence effects: the (i) material decomposition;
(ii)interfacial debonding; (iii) voids and cracks
in the material. When the composites had been
immersed in water, water molecules firstly en-
tered the free space of voids and cracks in the
composites, at the same time, water molecules
could rapidly pass through and diffuse along the
interface between the fibre and matrix owing to
the capillarity. The inter-facial bond strength
had been weakened by the plasticization effect
of the absorbed water. On the other hand, wa-
ter molecules would be attracted by the hydro-
philic groups in the flax fibre and the unsatu-
Fig. 3. Wetting rate of composites
Fig. 4. Impact load of composites
Fig. 5. Impact energy of composites
124 Functional materials, 23, 1, 2016
Wang Qiuhong et al. / Accelerated wet aging study ...
rated polyester. After longer time immersion in
water, hydrophilic groups of the polyester and
the flax fibre would have chemical reactions
with water molecules. The result suggested an
irreversible process might be the cause of the
property deterioration of the materials.
Compared to the original specimens, the
impact property of the two-and three-layer
plain composites for one-, two-,three-and six-
month was increased after immersion in water.
And the two-layer satin composites for one- and
six-month were increased. As was discussed
above, the deterioration of the matrix, the re-
inforcing material as well as the interface was
also unavoidable. However, the water may act
as a plasticiser to favor the impact property.
Compared with the original air molecules
trapped in the voids before water immersion,
water molecules would be more active in resist-
ing the impact action. Moreover, the specimens
tested after the withdrawal from the water
were not completely dried, this promoted to
the impact property because the wet flax was
swelling adequately and wet strength of flax is
much larger than its dry strength. Finally, the
complex curing and fabricating processes leaded
to the consolidation of the composites was in-
complete. After longer time immersion in water,
the unsaturated polyester may have oxidation
reactions with the oxygen in the water, which
may lead to an increase of the cross-linking
density of the matrix and further enhance the
impact property of the composites.
From Fig. (4) and Fig. (5), we can also see
that the two-layer plain and satin composites
appeared different results. The impact proper-
ties of the two-layer plain composites were in-
creased after immersion in the water. Those of
the two-layer satin composites was increased
for one-month and six-month and decreased
for two-month and three -month after immer-
sion in the water. The reason for the difference
of impact properties was owing to the fabric
structure. The plain was of the most crossing
point and the satin was of the longest float. The
plain and satin fabric with same warp count
and weft count were of different area weight
and thickness, the former 127.95 g/m2 and
0.59 mm and the latter 118.68 g/m2 and 0.75
mm, which were the major factors influencing
the impact property of composites. The two-
layer plain fabrics-reinforced composites were
possible of more voids and cracks and poorer in-
terface between fibre and matrix than the satin
fabrics-reinforced composites. In other words,
the plasticization effected by the water may be
contributed to the improvement of the impact
properties.
There was one exception of the data in the
Fig.4, compared to the other two-layer plain
specimens, the impact load of the two-layer
plain composites was increased a great deal
after two-month soaking in water. The higher
standard deviation showed an unsteady trend
which might be arisen by the experimental
error.
The panel layers and fabric structure may
influence the impact property testing results in
water durability studies if the duration of the
immersing time was relatively short.
4. Failure mode
Figure (6) and Figure (7) showed the SEM
images taken from the broken sections of the
two-layer plain specimens before and after the
water immersion respectively. Figure (8) and
Figure (9) showed the broken section of the
four-layer specimen before and after the water
treatment.
Fig. 6. Original two-layer Fig. 7. Two-layer for six-month
Functional materials, 23, 1, 2016 125
Wang Qiuhong et al. / Accelerated wet aging study ...
From Fig. (6) and Fig. (8) it can be seen that
the matrix was closely adhered with the flax
fibre bundle. Delamination between the fibre
and the matrix can’t be detected. During the
impact property test, no pull out of the fibres
from the matrix was found. All of these results
prove that the interface between the flax fibre
and the polyester matrix was perfect.
After six-month water immersion, Fig. (7)
showed that the flax fibres were still closely
been held by the polyester resin, no obvious
debonding had been found. The enhancement
effect of the wet flax fibre may be overweighed
by the degradation effect of the materials.
From Fig. (9), it can be seen that the inter-
face between the flax fibre and the UPR matrix
in the four-layer specimen was bare with fewer
adhered resin particles. This may illustrate that
debonding happened between the fibre and the
matrix. During the moisture absorption, water
molecules came into the free space of polymers
or micro-voids formed by cavities and cracks,
which induced more new macro-cavities and
cracks with time prolonged, thus the interface
was gradually damaged.
The results indicated that the materials had
experienced some forms of physical damage
and/or chemical degradation. The weakening of
bonding between fibre and matrix and soften-
ing of matrix material were also reasons of the
decreased composite property.
5. Conclusions
In this research, flax plain and satin fabrics
were used as reinforcement and unsaturated
polyester as matrix. The composites of two-,
three- and four-layer were fabricated respec-
tively by the VARI technique. The experiment
was illustrated that water molecules played a
significant role influencing the impact property
of the composites.
Most of the two- and three-layer plain and
the two- satin fabric-reinforced composites had
a relatively better water durability by the ex-
perimentation. Although the impact energy of
two-satin fabric-reinforced composites after
immersion was decreased by 5.1% for two-month
and 16.5 % for three-month, it was increased
by 34.6 % for six-month. The change of the im-
pact property of four-layer plain composites
was more outstanding than others. The im-
pact energy of the laminates after immersion
was decreased by 30.5 % for one-month, 33.8
% for two-month, 44.5 % for three-month and
2.0 % for six-month. The reason might be that
the water immersion aging affected the micro-
structural integrity of the laminated plates
causing numerous defects.
For the flax fabric composite aimed as im-
pact property in the humid environment, it was
not beneficial if the layer of material was added
in this experiment. It could be illustrated by
the reduced impact energy of the four-layer
composites resulted from the deteriorated
fibre, matrix and interface. The maximum
decrease rate of the impact property was
44.5%. For the four-layer laminates employed
in the research, the chemical reaction of the
water molecules with the fibre and the matrix
and the delamination damage caused by the
penetration of the moisture into the materials
would be faster and earlier.
For the material with suitable layers, the
serrate change of the impact property revealed
that there were conflict effects in the material.
When the composites were immersed in water,
the voids and cracks in the material would be
gradually filled with water molecules, and the
capillarity effect would encourage the water
Fig. 8. Original four-layer Fig. 9. Four-layer for three-month
126 Functional materials, 23, 1, 2016
Wang Qiuhong et al. / Accelerated wet aging study ...
penetration. With time prolonged, it was un-
derstood that chemical reactions would hap-
pen between the water molecules and the flax
fibre as well as the matrix. This would damage
the impact property of the laminates. On the
other hand, the water molecules were consid-
ered responsible for the increase of the impact
property with longer time water immersion.
The material was more even than the original
penal because of the filled voids and cracks by
the water molecules and the fibre and matrix
would be bonded with the hydroxyl group of
the water, this would resist the damage during
the impact testing. At the same time, the wa-
ter might work as a plasticizer for flax fibre to
resist the impact action resulting an increased
impact property. So the moisture durability of
the composites may be improved by the appli-
cation of the flax fibre.
Therefore moisture absorption should be
taken into consideration when flax fibre was
employed as the reinforcement in the compos-
ites because of its hydrophilic nature in order
to obtain reliable composite materials.
Acknowledgements
This work supported by Fund of Project of
Education Department of Liaoning Province,
China (No.2006B013). Liaoning province col-
leges’ outstanding talent support program (No.
LJQ2015008).
References
1. S. G, B. J and R. H. J.Thermopl. Comp. Mater,
9, 239, 1996.
2. M. A. Khan, M. M. Hassan, L. T. Drzal. Compos.
Part A: Appl. Scie. Manufact.,1, 71, 2005.
3. K. Oksman,M. Skrifvars, J. F. Selin. Compos.
Scie.Techn., 7, . 1317., 2003.
4. A. K. Bledzki, W. Zhang, A. Chate.Compos.. Sci.
Techn., 61, 2405, 2001.
5. M. M. Thwea, K. Liao. Compos. Sci. Techn., 63,
375, 2003.
6. C.Z. Paiva Junior, L.H. de Carvalho, V.M.
Fonseca et al. Polymer Test, 23, 131, 2004.
7. T.A. Bullions, D. Hoffman, R.A. Gillespie et al.
,Comp Sci Techn, 66, 102, 2006.
8. M. L. Bras, S. Duquesne, M. Fois et al. Polym.
Degrad.Stabi.,88, 80, 2005.
9. E. Baysal, M. K. Yalinkilic, M. Altinok et al.
Constr. Build. Mater., 21,1879, 2007.
10. M. J. John, S. Thomas. Carbm. Polym., 71, 343,
2008.
11. E. Rodriguez, R. Petrucci, D. Puglia et al. , J.
Comp. Mater., 39, 265, 2005.
12. C.P.L.Chow, X.S.Xing, R.K.Y.Li. Comp. Scie.
Techn, 67, 306, 2007.
13. Rouison D., Couturier M., Sain M. et al., Polym.
Comp., 26, 509, 2005.
14. E. Bodros, I. Pillin, N. Montrelay et al. Compos.
Scie. Techn., 67, 462, 2007.
15. X. Huang, A. Netravali, Comp. Scie. Techn., 67,
2005, 2007.
16. M. Baiardo, E. Zini, M. “Scandola, Comp. Part A:
Appl. Scie. Manufact., 6, 703, 2004.
17. T. Kawaguchi, R. A. Pearson, Comp. Scie. Techn.
64,1991, 2004.
18. Zhang Jihua, Zhan Maosheng, J.Comp. Mater.,
38, 779, 2004.
19. N.Godin, S.Huguet, R.Gaertner., Comp. Struct.,
72, 79, 2006.
20. A. Kootsooks, A. P. Mouritz, Comp.Scie.Techn,
64, 1503, 2004.
21. C. Suri, H. Hamada, K. Koyama, Adv.Comp.
Mater., 10, 63, 2001.
22. A. Hodzic, J.K. Kim, A. E. Lowe et al. , Comp
Scie. Techn., 64, 2185, 2004.
23. V. A. Alvarez, A. Vazquez, J.Comp. Mater., 38,
1165, 2004.
24. K. Imielinska, L. Guillaumat, Comp. Scie.Techn.,
64, 2271, 2004.
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