Role of boric acid for a poly (vinyl alcohol) film as a cross-linking agent: Melting behaviors of the films with boric acid

Miyazaki, Tsukasa; Takeda, Yuuki; Akane, Sachiko; Itou, Takahiko; Hoshiko, Akie; En, Keiko

doi:10.1016/j.polymer.2010.09.048

Cited by 114 publications

(76 citation statements)

References 29 publications

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“…The strain‐induced hardening occurs at a lower strain and the yield stress increases with increasing the boric acid concentration in the solutions, implying that the addition of boric acid to the solutions should result in cross‐linking between the PVA molecular chains. In our previous work, the increase in T g s for the films dried after immersion in boric acid aqueous solutions was also indicated as a result of cross‐linking the PVA molecular chains with boric acid . These cross‐links affect substantially the structural changes during film stretching.…”

Section: Resultsmentioning

confidence: 89%

“…Therefore, the 2‐D WAXD patterns obtained on stretching were integrated within 90° from vertical direction for obtaining the 1‐D radial diffraction profiles. Furthermore, as described in our early articles , 1‐D diffraction profiles were decomposed into two crystalline peaks (

true(101 true) true(10 \bar{1} true)

doublet and

true(200 true)

planes; the b‐axis is defined to be parallel to the chain direction) and one amorphous halo in the examined region, q = 10 − 18 nm −1 for the estimation of crystallinity. The peak type was chosen to be Gaussian.…”

Section: Discussionmentioning

confidence: 99%

“…In our previous work, with differential scanning calorimetry and simultaneous SAXS/WAXD measurements for the films on melting we investigated the role of boric acid penetrated into the PVA film when the film was dried after immersion in boric acid aqueous solutions . It was found that the boric acid additive slows down the PVA molecular motion, and hinders melting and recrystallization of the PVA molecules on melting for the dried films.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of oriented amorphous regions in polymer films during uniaxial deformation; structural characterization of a poly(vinyl alcohol) film during stretching in boric acid aqueous solutions

et al. 2014

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We have improved the conventional analytical method of the scattering data obtained with in‐situ synchrotron X‐ray scattering experiments, which is applicable to the structural characterization of the film during stretching. Four components of molecular chains in the film are divided from two‐dimensional wide‐angle X‐ray diffraction patterns. These components are the oriented crystals, the unoriented ones, the oriented amorphous chains, and the unoriented ones, respectively. This method allows to evaluate directly the degree of orientation of the amorphous chains and the amount of the oriented amorphous fraction in addition to each evaluation for the crystalline regions. This method is applied to the structural characterization of the poly(vinyl alcohol) (PVA) film during stretching in boric acid aqueous solutions, suggesting that boric acid accelerates orientation of molecular chains in the amorphous regions, and increases the oriented amorphous fraction by producing the cross‐links between the PVA chains and hindering strain‐induced crystallization. At a film break on stretching in the 3 wt% boric acid solution, the oriented amorphous fraction increases up to 70%, which is much higher compared to that in the film stretched in water, 45%. POLYM. ENG. SCI., 55:513–522, 2015. © 2014 Society of Plastics Engineers

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Section: Resultsmentioning

confidence: 89%

true(101 true) true(10 \bar{1} true)

doublet and

true(200 true)

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Evaluation of oriented amorphous regions in polymer films during uniaxial deformation; structural characterization of a poly(vinyl alcohol) film during stretching in boric acid aqueous solutions

et al. 2014

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“…During film formation, two moles of PVA containing hydroxyl groups were crosslinked with acidic groups of boric acid, while SA containing carboxylic groups (ACOOH) were crosslinked with Ca 12 ions of calcium chloride thus formed crosslinked polymeric network (IPN) 31,32 ( Figure 3).…”

Section: Synthesis Of Pva/sa Sprayed Hydrogel (Shd) Filmmentioning

confidence: 99%

Design and in vitro investigation of nanocomposite hydrogel based in situ spray dressing for chronic wounds and synthesis of silver nanoparticles using green chemistry

Kumar

Jaiswal

2015

J of Applied Polymer Sci

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An innovative concept of spontaneous film dressing has been designed as sprayed hydrogel dressings (SHD) using a blend of polyvinyl alcohol (PVA) and sodium alginate (SA) as synthetic and natural polymeric components and, were crosslinked with boric acid and calcium chloride, respectively. Silver nanoparticles (AgNPs) are synthesized by green chemistry using Ficus benghalensis extract (FB) and were characterized by SEM and zeta sizer. FTIR spectra show polymeric interaction with AgNP s , while SEM images show outer surface of the SHD film. Equilibrium swelling and degradation in aqueous media (distilled water and buffers) are found to be dependent upon PVA/SA ratio. Polymeric combination exhibit pseudoplastic behavior with Farrow's constant >1. Uniformly distributed AgNPs (particle size 27.55 6 2.01 nm), high water retention (13 fold), and biodegradable (5 days) nature of dressing along with sustained release profile of both AgNPs and extract with concentration-dependent antimicrobial activity have been observed for 24 h. Self shaped, biodegradable, aseptic, prolong anti-oxidative, non-hemolytic, blood compatible, and hemostatic properties of SHD film appears as promising dressing for superficial wounds.

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“…[1] PVOH (with high molecular weight and high degree of saponification) is used for polarizing films for liquid crystal displays. [2,3] PVOH is a biodegradable synthetic polymer, but the biodegradation rate is extremely slow. [4,5] However, PVOH can be compounded with other cheap renewable polymers, such as starch, to improve its biodegradation rate and to improve its price competitiveness.…”

Section: Introductionmentioning

confidence: 99%

Drying of Methanol and Methyl Acetate from Poly(vinyl alcohol) Flakes

Chen

Yoon

2014

Drying Technology

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Diffusion coefficients and equilibrium solubility of methanol/ poly(vinyl alcohol) (PVOH) and methyl acetate/PVOH systems were examined to predict the drying rate of the solutes from PVOH flakes. The diffusion coefficients of the solutes strongly depended on the concentration of the solutes in PVOH, and the concentration dependency was well-represented in the form of D ¼ D 0 exp aC bþC n o . Numerical integration of the diffusion equation was successful using the Tri Diagonal-Matrix Algorithm. Our analyses demonstrated that an increase in the drying temperature shortened the drying time, while a reduction of the dew point of the solute in the drying gas negligibly affected the drying rate due to the formation of dense skin. As the excessive elevation of drying gas temperatures would degrade PVOH product qualities, reduction of the flake thickness and/or addition of methyl acetate to the drying gas were suggested as efficient tools to increase the methanol drying rate.

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Role of boric acid for a poly (vinyl alcohol) film as a cross-linking agent: Melting behaviors of the films with boric acid

Cited by 114 publications

References 29 publications

Evaluation of oriented amorphous regions in polymer films during uniaxial deformation; structural characterization of a poly(vinyl alcohol) film during stretching in boric acid aqueous solutions

Evaluation of oriented amorphous regions in polymer films during uniaxial deformation; structural characterization of a poly(vinyl alcohol) film during stretching in boric acid aqueous solutions

Design and in vitro investigation of nanocomposite hydrogel based in situ spray dressing for chronic wounds and synthesis of silver nanoparticles using green chemistry

Drying of Methanol and Methyl Acetate from Poly(vinyl alcohol) Flakes

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