Effect of Plasticizers on Properties of Rice Straw Fiber Film

Effect of Plasticizers on Properties of Rice Straw Fiber Film

December 2014 ScienceDirect Vol. 21 No. 4 67-72 Journal of Northeast Agricultural University (English Edition) Available online at www.sciencedire...

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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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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]

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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

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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.

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