December 2014
ScienceDirect
Vol. 21 No. 4 67-72
Journal of Northeast Agricultural University (English Edition)
Available online at www.sciencedirect.com
Effect of Plasticizers on Properties of Rice Straw Fiber Film Chen Hong-rui, Chen Hai-tao*, Liu Shuang, Dun Guo-qiang, and Zhang Ying College of Engineering, Northeast Agricultural University, Harbin 150030, China
Abstract: In order to improve the properties of rice straw fiber film, one factor contrast test method was employed. Plasticizer type was chosen as input variable, dry tension strength and elongation, wet tension strength and elongation, bursting strength and tearing strength were chosen as indexes. The results showed that there were significant differences among the means of dry tension strength, dry elongation and bursting strength of different plasticizers; there were not significant differences among the means of wet tension strength, wet elongation and tearing strength of different plasticizers; for dry tension strength and elongation, glycerol had a significant difference with sorbitol and PEG, no significant difference was observed between sorbitol and PEG, dry tension strength added glycerol had been reduced 6.8% compared with that added sorbitol, reduced 9.5% compared with that added PEG; elongation had been improved 6.1% and 9.4%, respectively; for bursting strength, sorbitol had a significant difference with glycerol and PEG, no significant difference was observed between glycerol and PEG; bursting strength added glycerol and added PEG had been improved 6.9% and 5.6%, respectively compared with that of the added sorbitol. The results provided a theoretical reference for further improving the straw fiber film manufacturing process. Key words: rice straw, film, plasticizer, comparative test CLC number: S5
Document code: A
Article ID: 1006-8104(2014)-04-0067-06
films that use plant fiber as material. Products of these
Introduction
decomposed films can be used as organic fertilizer
In the latest years, with the wide use of mulching film,
Chu and Shi, 2007; Sun et al., 2000).
the problems existed are also emerging. Most of the
Plant fiber film has a definite strength without adding
films used currently are made of synthetic polymers,
any adhesives because of its own fiber strength, fiber
such as polyethylene and polyvinyl chloride (PVC),
bonding strength and the arrangement of the fibers. But
which can not be degraded themselves. Mass of plastic
unplasticized plant fiber films exist a rapid evapora-
piece residual in the soil lead to the destruction of soil
tion of water at the amorphous region and the cry-
structure, and cause great difficulties to plowing and
stalline region during the process of dryness. Cellulose
sowing (Zhou and Zhu, 2002; Han and Chen, 2008;
macromolecule draws closer gradually under the
Lu et al., 2007). To solve the problem generated by
effects of hydrogen bond and the Van Edward force,
plastic film, researches on biodegradable films attract
hydrogen bonds form directly by cellulose molecules
great attention. Microbes in the oil can decompose
increase, intermolecular force enhances greatly and
which will increase oil fertility (Yang and Chen, 2010;
Received 10 October 2014 Supported by the Fund of Science and Technology Research Project of the 12th Five-year Plan (2012BAD32B02-5) Chen Hong-rui (1990-), female, Master, engaged in the research of biomass material technology. E-mail:
[email protected] * Corresponding author. Chen Hai-tao, professor, supervisor of Ph. D student, engaged in the research of biomass material technology and agricultural mechanization engineering. E-mail: htchen@neau. edu. cn http: //publish.neau.edu.cn
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Journal of Northeast Agricultural University (English Edition)
Vol. 21 No. 4 2014
activation energy needed for macromolecule increases
China); ZT-400 Valli beater, Zhongtong Test Equip-
at the same time. Thus, lead to the difficulties of
ment Co., Ltd. (Shanxi, China); JA5003B electronic
deformation (Tan, 2001). So unplasticized plant fiber
balance, Tianmei Science and Technolory Instrument
film appears as a property of inflexibility, such as
Co., Ltd. (Shanghai, China); ZTG-100 pulp degree
crisping, hard and easy to tear. In order to solve the
test machine, ZCX-A paper sheet forming device,
problems, a plasticizing measure was often carried
ZL-300 pendulum paper tension strength test machine,
out, such as adding some low molecular alcohol
ZDNP-1 paper bursting strength test machine, and
compounds which can produce hydrogen bonding
ZSED-1000 paper tearing strength test machine,
force with OH groups on cellulose macromolecule
Yueming Small Test Machine Co., Ltd (Changchun,
to permeate into the inside of a film. That is hanging
China).
up numbers of low molecular alcohol compounds on molecular chain can enlarge the distance between
Methods
chains, weaken hydrogen bonding force of OH groups
One factor contrast test method was carried out with
on macromolecular chain, and improve the relative
plasticizer type as the input variable, dry and wet
sliding motion of the chains among macromolecules
tension strength, elongation, bursting strength and
(Tan, 2001; Zhang, 2007).
tearing strength of the rice straw fiber film as indexes.
In order to search for the effects of plasticizer on
According to references and results of the previous
properties of straw fiber film, screen out the optimum
tests, three plasticizers were chosen as followings,
plasticizer for making rice straw fiber film and provide
glycerol, sorbitol and PEG. Test data is shown in
theory reference for the manufacturing process
Table 1. Concentration of every plasticizer was 3%,
of straw fiber film, an experimental research on
additive amount of the wet strength agent and rosin
plasticization of rice straw fiber film with the method
were 1.6% and 0.4%, respectively, and additive amount
of adding plasticizer was carried out.
of the alumina was 4.5 times as rosin (Lv et al., 2012).
Materials and Methods
Procedure
Materials
of 2013 into 10 cm, soaked in normal atmospheric
Dongnong 425 rice straw was provided by Northeast
temperature for 12 h. Then, used D200 straw fiber
Agricultural University, Harbin, China; KP wood
preparation machine to produce coarse fiber.
fiber; glycerol (AR) was purchased from Jizhun
2) Beated rice straw fiber film and KP pulp board to
Chemical Reagent Co., Ltd. (Tianjin, China); Sorbitol
45 SR referring to QB/T3702-1999.
(biochemical reagent) was purchased from Bodi
3) Mixed the two kind pulps together with the
Chemical Reagent Co., Ltd. (Tianjin, China); PEG
additive amount of rice straw fiber 70% and KP pulp
was purchased from Guangfu Science and Technolory
70%, calculated the additive amount of every additive
Chemical Reagent Co., Ltd. (Tianjin, China); and wet
and then stirred the mixing pulp as added additives
strength agent was provided by Xinxing Chemical
into it (Cheng et al., 2009).
Plant (Mudanjiang, China).
4) Referring to QB/T3703-1999, used the well
1) Cut Dongnong 425 rice straw harvested in autumn
stirred pulp to make film samples with the ration of Equipment and instrument
80 g • m -2 . Then, put the film samples on drying
D200 type of the straw fiber extruder, manufactured by
machine for 2 min, sprayed different plasticizer liquor
Northeast Agricultural University; electronic scale,
on the surface of the film samples as they had not
Haikang Electronic Instrument Factory (Shanghai,
been dried completely. Exposed them under normal
E-mail:
[email protected]
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Chen Hong-rui et al. Effect of Plasticizers on Properties of Rice Straw Fiber Film
atmospheric temperature for 1 min and then to the
GB/T455 to measure tearing strength. Every experi-
bead machine to be pressured for 3 min to make fibers
ment was taken for five times. Used Design-Expert
combine more closely. Again, put film samples on the
software to make statistical analyses of the data.
drying machine to be dried completely. 5) Referred GB/T453 to measure the dry, wet tension strength and elongation of the film sample, referred GB/T454 to measure bursting strength, and referred
Results and Discussion Results of the experiment are shown in Table 1.
Table 1 Test factors and data Factor
Response Dry tension strength (N) y1
Dry elongation (%) y2
Wet tension strength (N) y3
Wet elongation (%) y4
Bursting strength (Pa×103) y5
Tearing strength (N×10-3) y6
Glycerol
27.6±0.79
1.75±0.03
11.2±0.39
2.60±0.04
87±1.60
188.1±2.52
Sorbitol
29.6±0.79
1.65±0.03
11.4±0.39
2.55±0.04
81±1.60
187.4±2.52
PEG
30.5±0.79
1.60±0.03
11.6±0.39
2.55±0.04
86±1.60
182.6±2.52
Plasticizer
of Prob>F less than 0.1 indicated that factor had a Analyses of variance
significant difference on the indexes; and the value
Results of ANOVA are shown in Table 2.
of Prob>F more than 0.1 indicated that factor had no
For the given significant level of 0.1, the value
significant difference on the indexes.
Table 2 Analyses of variance Response
y1
y2
y3
y4
y5
y6
df
Mean square
F value
Prob>F
22.030
2
11.0200
3.57
0.0608
37.060
12
3.0900 6.36
0.0131
0.26
0.7771
0.67
0.5285
3.49
0.0637
1.27
0.3169
Source
Sum of square
Factor Error Total
59.090
14
Factor
0.058
2
0.0290
Error
0.055
12
0.0046
Total
0.110
14
Factor
0.400
2
0.2000
Error
9.320
12
0.7800
Total
9.720
14
Factor
0.012
2
0.0060
Error
0.110
12
0.0089
Total
0.120
14
Factor
89.200
2
44.6000
Error
153.200
12
12.7700
Total
242.400
14
Factor
80.130
2
40.0700
Error
379.620
12
31.6300
Total
459.750
14 http: //publish.neau.edu.cn
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Vol. 21 No. 4 2014
Journal of Northeast Agricultural University (English Edition)
Therefore, from Table 2, we could conclude that
different plasticizers.
there were significant differences among the means of dry tension strength, dry elongation and bursting
Effect of different plasticizers on dry tension
strength of different plasticizers; there were not
strength and elongation
significant differences among the means of the wet
Results of multiple comparisons are shown in Tables 3
tension strength, wet elongation and tearing strength of
and 4.
Table 3 Multiple comparisons of different plasticizer effects on dry tension strength Treatment
Mean difference
df
Standard error
t value
Prob>|t|
Significance
1 VS 2
–2.00
1
1.11
–1.80
0.0971
Significance
1 VS 3
–2.90
1
1.11
–2.61
0.0228
Significance
2 VS 3
–0.90
1
1.11
–0.81
0.4338
Table 4 Multiple comparisons of different plasticizer effects on elongation Treatment
Mean difference
df
Standard error
t value
Prob>|t|
Significance
1 VS 2
0.100
1
0.043
2.34
0.0377
Significance
1 VS 3
0.150
1
0.043
3.50
0.0044
Significance
2 VS 3
0.050
1
0.043
1.17
0.2656
As shown in Tables 3 and 4, for dry tension strength
by decreasing the gravitation of the molecule chains
and elongation, glycerol had a significant difference
or reducing the crystalline of the polymer molecule
with sorbitol and PEG, no significant difference was
chains. Thus, rice straw fiber film appeared as the
observed between sorbitol and PEG at the significant
decrease of the tension strength and the increase of
level of 0.1. As shown in Table 1, the order of the dry
the elongation on a macro level (Yu, 1990; Han et al.,
tension strength of the rice straw fiber film added with
2011; Chen et al., 2013). At the same time, glycerol
3% different plasticizers was PEG>sorbitol>glycerol,
was tribasic alcohol, sorbitol was hexabasic alcohol,
and the order of elongation was glycerol>sorbitol>
while PEG was polymer. Cellulose was polymer of the
PEG. From the multiple comparison results, glycerol
multi hydroxyl glucose, three-dimensional regular high
had a significant difference with sorbitol and PEG,
polymer connected by anhydrous glucose residues
dry tension strength added glycerol had been reduced
through β1, 4 glucosidic bond. The motion resistance
6.8% compared with that added sorbitol, reduced 9.5%
of it was hydrogen bond in and between molecules.
compared with that added PEG; elongation had been
Glycerol was the smallest molecule of these three
improved 6.1% and 9.4%, respectively. It was because
which could insert into molecule chains more easily
small molecular alcohols inserted into the chains of
compared with the other two (Shi and He, 2004; Zhan
the plant film, enlarged the distance of the molecules
and Zhao, 2009; Zeng and Wu, 2006). To further
and finally weakened the force of the plant fiber
improve the plasticization of the rice straw fiber film
molecules. The main factors against plasticization
on the premise of the tension strength, according to
were gravitation and crystalline of the polymer
the mean results, only the film added with 3% PEG
molecule chains, so plasticization could be improved
whose dry tension strength larger than 30 N could
E-mail:
[email protected]
·71·
Chen Hong-rui et al. Effect of Plasticizers on Properties of Rice Straw Fiber Film
meet the mechanical performance for laying field. The
different plasticizers was PEG>sorbitol>glycerol, and
elongation of it was 1.6%, enhanced 0.35% compared
the order of elongation was glycerol>sorbitol>PEG.
to that not be plasticized. So PEG was given priority as
From the analyses of variance, no significant
the optimum plasticizer of rice straw fiber film. If the
difference was observed between wet tension strength
film demanded a higher plasticization and considering
and elongation of different plasticizers. It might be
economical efficiency, glycerol was the optimum
that water molecules inserted into cellulose molecule
plasticizer of the rice straw fiber film, elongation of
chains in place of the plasticizer molecules in wet
the film enhanced 0.5% compared with that not be
condition that made the effect of plasticizers was not
plasticized.
so significant as in dry condition (Jin, 2009; Wang et al., 2013; Sun et al., 2010; Gong et al., 2008).
Effect of different plasticizers on wet tension strength and elongation
Effect of different plasticizers on bursting
As shown in Table 1, the order of the wet tension
strength and tearing strength
strength of the rice straw fiber film added with 3%
Results of multiple comparisons are shown in Table 5.
Table 5 Multiple comparisons of different plasticizer effects on bursting strength Treatment
Mean difference
df
Standard error
t value
Prob>|t|
Significance
1 VS 2
5.60
1
2.26
2.48
0.0291
Significant
1 VS 3
1.00
1
2.26
0.44
0.6660
2 VS 3
–4.60
1
2.26
–2.04
0.0645
Significant
As shown in Table 5, for bursting strength, sorbitol
the lowest of these three, so glycerol was the optimum
had a significant difference with glycerol and PEG, no
plasticizer of rice straw fiber film from the economic
significant difference was observed between glycerol
point of view.
and PEG, at the significant level of 0.1. Addition of plasticizers reduced the brittleness of rice straw fiber film, gave it a certain tenacity and
Conclusions
strength, and improved the bursting strength of it. As
There were significant differences among the means
shown in Table 1, the order of the bursting strength
of the dry tension strength, dry elongation and
of the rice straw fiber film added with 3% different
bursting strength of the different plasticizers; there
plasticizers was glycerol>sorbitol>PEG, bursting
were not significant differences among the means of
strength added glycerol and PEG had been increased
the wet tension strength, wet elongation and tearing
6.9% and 5.6%, respectively compared with that added
strength of different plasticizers; for dry tension
sorbitol. Combined with the results of the multiple
strength and elongation, glycerol had a significant
comparisons, no significant difference was observed
difference with sorbitol and PEG, no significant
between glycerol and PEG on bursting strength.
difference was observed between sorbitol and PEG,
For tearing strength, no significant difference was
dry tension strength added glycerol had been reduced
observed among different plasticizers. If considering
6.8% compared with that added sorbitol, reduced
bursting strength, both glycerol and PEG could be
9.5% compared with that added PEG; elongation
chosen as plasticizers. But the price of glycerol was
had been improved 6.1% and 9.4%, respectively; for http: //publish.neau.edu.cn
·72·
Journal of Northeast Agricultural University (English Edition)
bursting strength, sorbitol had a significant difference
Vol. 21 No. 4 2014
Fine Chemical Materials and Intermediate, 12: 31-33.
with glycerol and PEG, no significant difference was
Lu J G, Wang Z Y, Yi Y. J 2007. Application status on farm-oriented
observed between glycerol and PEG; bursting strength
film and research progress on degradable film. Chinese Hemp
added glycerol and PEG had been improved 6.9% and
Science, 29(3): 150-152.
5.6%, respectively compared with that added sorbitol.
Lv G H, Bai W B, Guo J Y, et al. 2012. Research status and
On the present basis of the rice straw fiber film
development trend analysis of paper film in China. Agricultural
manufacturing process, adding 3% PEG to film could
Mechanization Research, 9(9): 249-252.
enhance elongation and bursting strength by 0.35
Shi S L, He F W. 2004. Analysis and detection of pulping and
and 16%, respectively, as tension strength could also
papermaking. Chinese Light Industry Publishing Company, Beijing.
meet the mechanical performance for laying field
pp. 13-84.
at the same time. Properties of the film was promoted further.
Sun B X, Xiang B, Han C Y, et al. 2010. Effect of plasticizers on mechanical properties of biodegradable film based on high amylase starch. Science and Technology of Food Industry, 4: 320-322.
References Chen H T, Zhang Y, Huang Z H, et al. 2013. Effect of moisture content on flow dynamic properties of rice straw. Journal of Northeast Agricultural University, 44(11): 90-94. Cheng F, Zhen W J, Pan P, et al. 2009. Study on functional cellulose materials. Leather Science and Technology, 19(1): 27-31. Chu W H, Shi Y H. 2007. Effect, influence and strategy of agricultural film on agricultural production. Inner Mongolia Agricultural Science and Technology, 7: 142-143. Gong Z Q, Li Y C, Zhu D Y. 2008. Effect of plasticizers on physical properties of chitosan and gelatin mixing film. Science and Technology of Food Industry, 29(3): 231-233. Han Y J. 2011. Study on techniques of rice straw membrane production and its properties. Northeast Agricultural University, Harbin. Han Y J, Chen H T. 2008. Development status and reflection on paper film at home and abroad. Agricultural Mechanization Research, 164(12): 244-249. Han Y J, Chen H T, Liu L X, et al. 2011. Optimization of technical parameters for making mulch from rice straw fiber. Transactions of the CASE, 27(3): 242-247. Jin D. 2009. Research progress on environmental friendly plasticizers.
E-mail:
[email protected]
Sun J P, Chen X H, Hu Y H. 2000. Research progress of degradable agricultural film. New Chemical Materials, 28(7): 3-5. Tan C R. 2001. Research on manufacturing degradable film of bagasse. Guangxi University, Guangxi. pp. 31. Wang X, Cao L K, Yan M Z, et al. 2013. Effect of plasticizers on mechanical properties of biodegradable film. Processing of Agricultural Products, 7: 4-6. Yang J L, Chen H T. 2010. Application of agricultural straw on paper making industry. Heilongjiang Paper, 1: 29-32. Yu L. 1990. Discussion on plasticizing mechanization and content control of cellophane plasticize. Artificial Fiber, 6: 10-15. Zeng F C, Wu J. 2006. Effect of plasticizers on structure and properties of cellulose film. Packaging Engineering, 7(9): 16-23. Zhan X L, Zhao G H. 2009. Effect of plasticizers on mechanical and permeating properties of sweet potato starch film. Science and Technology of Food Industry, 6(11): 255-258. Zhang Q. 2007. Production process of epoxy plasticizer and the application of it in PVC plastic manufacture. Polyvinyl Chloride, 35(12): 1-4. Zhou J H, Zhu H W. 2002. Research and application on paper film. Farm-oriented Paper Film, 11(5): 56-58.