Effects of low poly(vinyl alcohol) content on properties of biodegradable blowing films based on two modified starches

2015 ◽  
Vol 30 (7) ◽  
pp. 1017-1030 ◽  
Author(s):  
Wentao Wang ◽  
Hui Zhang ◽  
Yangyong Dai ◽  
Hanxue Hou ◽  
Haizhou Dong

Biodegradable films from hydroxypropyl distarch phosphate (HPDSP)/poly(vinyl alcohol) (PVA) and cationic starch/PVA blends were obtained by extrusion blowing at ratios of 100:0, 95:5, 90:10, 85:15, and 80:20. The morphology, X-ray patterns, transparency, mechanical properties, thermal properties, and water vapor permeability (WVP) of the films were measured and compared. Scanning electron microscopic micrographs of the films showed continuous matrix texture as well as better compatibility between modified starches and PVA. X-Ray diffraction indicated the formation of ordered crystalline structures in the films during extrusion blowing. The addition of PVA to modified starches significantly increased their tensile strength (TS, 3.92 MPa) while decreasing their water vapor permeability (WVP, 3.23 × 10−10 g m−1 s−1 Pa−1). The starch/PVA composite films did not show phase separation.

2016 ◽  
Vol 10 (3) ◽  
pp. 311-316
Author(s):  
Anatoly Olkhov ◽  
◽  
Alexey Iordanskii ◽  

The structure of extruded films based on blends of polyvinyl alcohol and poly(3-hydroxybutyrate) (PHB) was studied for various compositions. The methods of DSC and X-ray analysis were used. As the phase-sensitive characteristics of the composite films, diffusion and water vapor permeability were also investigated. In addition, the tensile modulus and relative elongation-at-break were measured. Changes in the glass transition temperature of the blends and constant melting points of the components show their partial compatibility in intercrystallite regions. At the content of PHB in the composite films equal to 20–30 wt % their mechanical characteristics and water diffusion coefficients are dramatically changed. This fact, along with the analysis of the X-ray diffractograms, indicates a phase inversion in the above narrow concentration interval. The complex pattern of the kinetic curves of water vapor permeability is likely to be related to additional crystallization, which is induced in the composite films in the presence of water


Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 219
Author(s):  
Yining Wang ◽  
Jinhui Li ◽  
Xin Guo ◽  
Haisong Wang ◽  
Fang Qian ◽  
...  

Poor water-vapor barriers and mechanical properties are common problems of biobased films. To maintain food quality, the barrier and its strength performance need to be improved. Tea polyphenols (TP) are a natural active substance, and their benzene ring structure provides a barrier for them as a film material. Films that incorporate TP also have enriched functionalities, e.g., as antioxidants. Here, active poly (vinyl alcohol) (PVA)-hemicellulose (HC)/TP films with good moisture resistance and antioxidant capacity were prepared via ultrasound assistance. The effects of TP incorporation and ultrasonication on the physical, antioxidant, and micromorphological properties of the films were investigated. Results showed that the addition of TP improved the thermal stability and water-vapor permeability (WVP) of the composite films. When a PVA-HC/TP composite film with a PVA-HC to TP mass ratio of 100:10 was treated with ultrasonication for 45 min, tensile strength was 25.61 Mpa, which was increased by 54% from the film without any treatment, and water-vapor permeability (WVP) value declined from 49% to 4.29 × 10−12 g·cm/cm2·s·Pa. More importantly, the films’ DPPH scavenging activity increased to the maximal levels of 85.45%. In short, these observations create a feasible strategy for preparing high-performance biodegradable active-packaging films.


2015 ◽  
Vol 35 (8) ◽  
pp. 765-771 ◽  
Author(s):  
Anatoly A. Ol’khov ◽  
Alexey L. Iordanskii ◽  
Tamara P. Danko

Abstract The morphology of extruded films based on blends of polyvinyl alcohol (PVA) and poly(3-hydroxybutyrate) (PHB) was studied for various compositions. The methods of differential scanning calorimetry (DSC) and X-ray analysis were used. The phase-sensitive characteristics of the composite films, diffusion and water vapor permeability were also investigated. Processes of binding of water and swelling cause the first areas; processes of a relaxation and transition of structure of composites to an equilibrium condition, the second. In addition, the tensile modulus and relative elongation-at-break were measured. Changes in the glass transition temperature (Tg) of the blends and constant melting points of the components show their partial compatibility in intercrystalline regions. At a content of PHB in the composite films equal to 20–30% wt., the mechanical characteristics and water diffusion coefficients are dramatically changed. This fact, along with the analysis of the X-ray diffractograms, indicates a phase inversion in the above narrow concentration interval. The complex pattern of the kinetic curves of water vapor permeability is likely to be related to additional crystallization, which is induced in the composite films in the presence of water.


2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Xiao-feng Chen ◽  
Jun-li Ren ◽  
Ling Meng

A series of composite films were prepared using poly(vinyl alcohol) (PVA) and xylan as degradable raw materials under the addition of glycerol and ammonium zirconium carbonate (AZC). The influences of AZC on the mechanical properties, water-resisting properties, thermal stability, solubility (S), and water vapor permeability of PVA/xylan composite films were comparatively discussed. The results showed that AZC had a positive impact on improving the water resistance and mechanical properties of composite films especially for elongation at break (EAB). With increasing the AZC amounts from 0% to 15%, EAB increased rapidly from 18.5% to 218.0%, and theSvalues decrease from 11.64% to 8.64%. When the AZC amount reached 15%, the tensile strength still performed well (22.10 MPa). The great compatibility of components in composite films was also observed. Moreover, the addition of AZC had great influences on the thermal stability of composite films and the degradation in soil.


2010 ◽  
Vol 96 ◽  
pp. 75-79 ◽  
Author(s):  
Jun Feng Su ◽  
Wen Long Xia ◽  
Wen Li ◽  
Ke Man Jin

The aim of the present work was to investigate the moisture sensitivity of soy protein isolate (SPI) films blending with poly (vinyl alcohol) (PVA) plasticized by glycerol. Water vapor permeability (WVP) was measured based on the contents of PVA and glycerol in films. WVP values of various SPI/PVA films with/without glycerol were in the range of 8.25 and 10.9 g mm/m2 h kPa. The results showed that WVP values decreased with the increasing content of PVA. Moreover, XRD tests confirmed that the glycerol would insert into the macromolecular blending structure and destroy the crystalline of blends, and the crosslinkage between glycerol molecules and SPI reduced the interstitial spaces in protein matrix, thus allowing for decreasing diffusion rate of water molecules through the films.


Author(s):  
Jie Liu ◽  
Yanchun Liu ◽  
Eleanor M. Brown ◽  
Zhengxin Ma ◽  
Cheng-Kung Liu

The leather industry generates considerable amounts of solid waste and raises many environmental concerns during its disposal. The presence of collagen in these wastes provides a potential protein source for the fabrication of bio-based value-added products. Herein, a novel composite film was fabricated by incorporating vegetable-tanned collagen fiber (VCF), a mechanically ground powder-like leather waste, into a chitosan matrix and crosslinked with genipin. The obtained composite film showed a compact structure and the hydrogen bonding interactions were confirmed by FTIR analysis, indicating a good compatibility between chitosan and VCF. The optical properties, water absorption capacity, thermal stability, water vapor permeability and mechanical properties of the composite films were characterized. The incorporation of VCF into chitosan led to significant decreases in opacity and solubility of the films. At the same time, the mechanical properties, water vapor permeability and thermal stability of the films were improved. The composite film exhibited antibacterial activity against food-borne pathogens. Results from this research indicated the potential of the genipin-crosslinked chitosan/VCF composites for applications in antimicrobial packaging. 


Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2093
Author(s):  
Long Mao ◽  
Jianda Xie ◽  
Huiqing Wu ◽  
Yuejun Liu

Inspired by complexation and mussel adhesion of catechol groups in tannic acid (TA), organophilic layered double hydroxides (LDHs@TA-Ti) were synthesized by forming a one-pot assembled TA-titanium (Ti) dual network coating on the surface of layered clay for the first time. LDHs@TA-Ti/poly(vinyl alcohol) (PVA) nanocomposites were prepared by the solution casting method. The results show that TA-Ti(IV) and TiO2 coordination compounds are simultaneously formed due to hydrolysis of titanium tetrachloride and complexation of TA in aqueous solution. Upon TA-Ti coatings onto the surface of LDHs, the antibacterial rate of LDHs@TA-Ti is up to 99.98%. Corresponding LDHs@TA-Ti/PVA nanocomposites also show outstanding antibacterial properties. Compared with pure PVA, LDHs@TA-Ti/PVA nanocomposites show a 40.9% increase in tensile strength, a 17.5% increase in elongation at break, a 35.9% decrease in oxygen permeability and a 26.0% decrease in water vapor permeability when adding 1 wt % LDHs@TA-Ti. UV transmittance (at 300 nm) of LDHs@TA-Ti/PVA nanocomposites decrease by 99.4% when the content of LDHs@TA-Ti reaches 3 wt %. These results indicate that PVA matrix incorporated with LDHs@TA-Ti could be used as a potential active packaging material to extend the shelf life of food products.


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