Water absorption and its effect on the tensile properties of tapioca starch/polyvinyl alcohol bioplastics

Judawisastra, Hermawan; Sitohang, Ramona; Marta, L.; Mardiyati,

doi:10.1088/1757-899x/223/1/012066

Cited by 31 publications

(20 citation statements)

References 10 publications

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“…Based on Figure 4, the water uptake of the films after 24 h of immersion in distilled water showed a decreasing trend as the starch content was reduced. This trend is consistent with other similar studies 11,22 . The main explanation to this trend was the natural hydrophilic character of starch, which was responsible for the water uptake of the bioplastic films 11 .…”

Section: Resultssupporting

confidence: 93%

Corn starch/PVA bioplastics—The properties and biodegradability study using Chlorella vulgaris cultivation

Lim

Kiew

Lam

et al. 2021

Asia-Pacific J Chem Eng

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In this study, a biodegradable alternative to synthetic plastics was explored, where gelatinized corn starch was blended with polyvinyl alcohol (PVA) using the solution casting method at different ratios. Tensile tests showed that films made of only starch exhibited the lowest tensile strength at 3.66 MPa, which increased as the ratio of PVA in the blend was raised. The water vapor transmission rate was similar even when the starch content was changed. PVA was shown to increase the solubility of the film in water, and starch demonstrated a better ability to absorb water than that of PVA, with the pure starch film swelled up to 167% of its original weight. Fourier transform infrared (FTIR) analysis revealed that there was no significant chemical interaction between the starch and PVA which could alter their respective functional groups. Bioplastic films made of only starch showed the least amount of degradation after 3 days when buried in soil, while water uptake in films made of PVA caused it to turn into a sticky gel‐like substance. Chlorella vulgaris exhibited a higher preference for PVA as the substrate when compared to starch. This revealed that C. vulgaris showed promise as a candidate for breaking down the bioplastic films when grown as a heterotroph.

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Section: Resultssupporting

confidence: 93%

Corn starch/PVA bioplastics—The properties and biodegradability study using Chlorella vulgaris cultivation

Lim

Kiew

Lam

et al. 2021

Asia-Pacific J Chem Eng

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“…This band overlaps with the C─H stretching peak from alkyl groups from 2800 to 3000 cm −1. The peak from 1708 cm −1 corresponding to C═O from residual acetate groups is not found for our sample as a result of the high hydrolysis degree . The band noticed at 1141 cm −1 is ascribed to C─O stretching, while at 1324 and 1417 cm −1 , the C─H wagging of CH 2 and CH 2 stretching are observed, respectively.…”

Section: Resultsmentioning

confidence: 60%

Induced birefringence of rubbed and stretched polyvinyl alcohol foils as alignment layers for nematic molecules

Nechifor

Postolache

Albu³

et al. 2019

Polymers for Advanced Techs

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Some optical properties of poly (vinyl alcohol) (PVA) films are investigated prior and after the rubbing and stretching of the samples. Birefringence of the prepared foils is enhanced as their stretching degree and rubbing become larger. These processing factors are also affecting the values of the ordinary and extraordinary refractive indices. The induced anisotropy in PVA foils is evidenced in the morphological characteristics observed by optical microscopy. The spreading and adhesion behaviors of a nematic liquid crystal on PVA foils are analyzed by means of contact angle measurements. Preliminary testing of the nematic on the PVA films revealed significant variations in transmitted light intensity during sample rotation under crossed polarizers. The high contrast between dark and bright patterns is indicative of uniform and homogenous alignment of nematic on the rubbed and stretched PVA foils. KEYWORDS polyvinyl alcohol, birefringence, rubbed, stretching, alignment layer 1 | INTRODUCTION Among the applications of the most known hydrosoluble synthetic polymers, polyvinyl alcohol (PVA) has been used in display industry. 1 Liquid crystal display (LCD) devices are optoelectrical systems, which are mainly working based on the light-modulating properties of nematic liquid crystals (NLCs). 2 The cell contains a liquid crystal (LC) layer placed between two alignment layers (ALs) casted on indium tin oxide (ITO)-covered glass substrates. 3 The cell also contains polarizing plates, electrodes, retardation films, color filters, backlight unit, etc. In the fabrication technology of the LCDs, PVA films are used to manufacture polarizers, 4 retarders, 5,6 optical filters, 7,8 and ALs. 9-12 The ALis a polymer layer coated on the glass plates, which through its textured surface is able to align the NLC molecules. In the absence of AL layers, the NLC molecules would be disposed to orient themselves randomly. 13 The capacity to control the alignment of the NLC on AL surfaces is essential for the performance of LCDs since it is known that weak anchoring of the NLC can significantly reduce the operating voltages and can improve the steepness of the electro-optic response of device. 14 Because NLC molecules follow the alignment imposed by the surface pattern of AL, 1 various techniques were developed to control the NLC orientation through adaptation of the AL surface characteristics. Among these methods, the most reliable ones are stretching, 11 soft lithography, 15 photolithography, 16 nanoimprint lithography, 17 and rubbing. 18 The alignment of NLCs on a surface is affected by the polymer chemical structure and conformation 10,19,20 rubbing strength, 21 type of rubbing cloth, 18,22,23 film thickness, 9 surface roughness anisotropy, 24 and surface wetting characteristics. 25 Currently the display market still uses the rubbing procedure to prepare ALs. The process is quite simple and involves a close contact between the polymer film and the velvet covered rotating cylinder. 26 The pattern formed on the surface of the rubbed polym...

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“…Despite the growing interest in bioplastics, the use of starch-based plastic is still limited due to its brittleness and moisture sensitivity. Addition of polyvinyl alcohol (PVA) reduces the brittleness of the bioplastic [57], and latex increases water resistance [58]. Shi and Tang [47] used polyvinyl alcohol solution with styrene-butadiene (SBR) latex and polymeric methyl diphenyl diioscyanate to modify corn starch.…”

Section: Use Of Starch and Starch Derivatives As Substitutes Formentioning

confidence: 99%

Formaldehyde Use and Alternative Biobased Binders for Particleboard Formulation: A Review

Kariuki

Wachira

Kawira

et al. 2019

Journal of Chemistry

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Formaldehyde-based resins are conventionally used as a binder in formulation of particleboard. Epidemiologic studies have shown that formaldehyde is carcinogenic. Efforts to reduce the health hazard effects of the fomaldehyde-based resin in the particleboard formulation have included use of scavengers for formaldehydes and use of an alternative binder. Use of scavengers for the formaldehyde increases the cost and maintenance of particleboard formulation. There is no proof that scavengers eliminate the emission of formaldehyde from particleboard. Use of biobased binders in particleboard formulation provides an alternative for eliminating use of the formaldehyde-based resin. However, the alternative is hindered by challenges, which include limitations of physical and mechanical properties. The challenge has continuously been acted upon through research. The paper presents an overview of the use of starch as an alternative binder. Improvement over time of the starch and limitations thereof requires to be addressed. Use of the modified starch has shown increased particleboard performance. Mechanical strength, such as modulus of rupture, modulus of elasticity, and internal bonding in particleboards, however, remains to be a challenge.

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Water absorption and its effect on the tensile properties of tapioca starch/polyvinyl alcohol bioplastics

Cited by 31 publications

References 10 publications

Corn starch/PVA bioplastics—The properties and biodegradability study using Chlorella vulgaris cultivation

Corn starch/PVA bioplastics—The properties and biodegradability study using Chlorella vulgaris cultivation

Induced birefringence of rubbed and stretched polyvinyl alcohol foils as alignment layers for nematic molecules

Formaldehyde Use and Alternative Biobased Binders for Particleboard Formulation: A Review

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