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Jie Zhu - One of the best experts on this subject based on the ideXlab platform.

  • controlling Plasticizer Migration based on crystal structure and micromorphology in propionylated starch based food packaging nanocomposites
    Carbohydrate Polymers, 2021
    Co-Authors: Yujia Liu, Shuyan Zhang, Siqian Chen, Jie Zhu
    Abstract:

    Abstract Migration of additives is an important issue for proper application in food packaging. In this work, propionylated waxy and normal starch-based nanocomposites (PW-N and PN-N) with two different amylopectin content were immersed in distilled water, and structural changes and Migration mechanism of Plasticizer (triacetin) were discussed in detail. Results showed that when immersion time was prolonged to 150 h, small crystals of PN-N disappeared, and amorphous structures formed gradually in PW-N and PN-N. Exfoliated structures still remained in PW-N with prolonged immersion time, while exfoliated structures gradually formed from intercalated ones in PN-N, and the peak representing d001 (d-spacing) at q = 1.70 nm−1 faded. The Migration mechanism of triacetin obeyed the first-order kinetic model and Fick's law; furthermore, in comparison with PW-N, PN-N showed a larger diffusion coefficient (D2 = 12.13 μm2·h−1). These results contributed to expanding the application of starch-based nanocomposites in future environmentally friendly food packaging.

  • mathematical modelling of Plasticizer Migration and accompanying structural changes within starch ester nanocomposites
    Food Packaging and Shelf Life, 2021
    Co-Authors: Shuyan Zhang, Jie Zhu, Yujia Liu, Siqian Chen
    Abstract:

    Abstract Migration is an important issue for the security in food packaging. In this work, the Migration mechanism of Plasticizer in G50 starch ester nanocomposites and accompanying multi-scale structural changes were probed with immersion. Mathematical model manifested that the Migration mechanism of Plasticizer obeyed the first-order kinetic model, and the Migration of Plasticizer followed the Fick’s second law in the short-term Migration. In the meantime, the interactions between G50 starch ester and nanoparticles (OMMT) were enhanced by the Migration, which was in favor of reducing the Migration and bringing about a smaller diffusion coefficient (D) in the long-term Migration compared with short-term ones. Meanwhile, the strengthened interactions conduced to accelerating the motion of starch ester, and altering the dispersion of OMMT, which resulted in the transformation from intercalation to exfoliation with the vanish of small inter-planar spaces for crystals. Simultaneously, these conversions increased the electron density contrast in amorphous and ordered regions, showing an increment of the roughness with wrinkles in the cross-sections. Based on above researches, the Migration behaviors of Plasticizer in starch ester nanocomposites were well expounded, while it is still necessary to explore new ways to inhibiting the Migration of Plasticizer in food packaging materials.

  • effect of amylose amylopectin ratio of esterified starch based films on inhibition of Plasticizer Migration during microwave heating
    Food Control, 2017
    Co-Authors: Yiping Zhong, Ling Chen, Chen Huang, Siyuan Liu, Jie Zhu
    Abstract:

    Plasticizer, as a necessary processing aid in producing packaging materials, migrated into food stuffs, which caused food safety problems. In order to restraint Plasticizer Migration, the hydrophobic esterified starch-based films with different multi-scale structures were prepared by regulation the ratio of amylose and amylopectin. The influence of multi-scale structures including molecular interactions between Plasticizer and esterified starch, crystalline structure and aggregation structure on inhibition of diethyl phthalate (DEP) Migration during microwave heating was studied. As the strongest molecular interactions between starch and DEP, the amount of Plasticizer Migration in waxy film was lower than that of G50 film and G80 film. Even the largest size of micro-ordered region impeded the DEP movement in G50 film, the serious further amorphization in G50 film amorphous region in microwave process and weaker molecular interactions led to higher DEP Migration compared with that of waxy film. The amount of DEP Migration in G80 film were the largest which resulted from weaker molecular interactions, damaged crystalline structure during microwave process and the smallest size of micro-ordered region. This study provided a new method to control DEP Migration which favored the application of esterified starch-based biodegradable material for food packaging.

  • multi scale structural changes of starch based material during microwave and conventional heating
    International Journal of Biological Macromolecules, 2016
    Co-Authors: Jie Zhu, Shuyan Zhang, Binjia Zhang
    Abstract:

    This work revealed the influence of thermal processing on the microstructural, mesoscopic and molecular scale structures and thus the Plasticizer Migration of the starch ester films. Thermal processing promoted the permeation of water molecules to hinder the shrink of the amorphous macromolecules. That is, the swelling of the amorphous macromolecules diminished the ordered regions to a certain degree, resulting in the enlarged amorphous regions. Along with slight degradation of the macromolecules, the crystallites were partially disorganized, as indicated by a reduced relative crystallinity. These multi-scale structural changes of the films and the thermally enhanced mobility of Plasticizer molecules synergistically enhanced the Plasticizer Migration. This study not only enables a well understanding of how thermal treatment alters the Plasticizer Migration of starch-based films from a multi-scale structural view, but also hints to our future work that rationally modulating the structural features of starch-based film may effectively control the Migration of chemicals.

  • Inhibition of Plasticizer Migration from packaging to foods during microwave heating by controlling the esterified starch film structure
    Food Control, 2016
    Co-Authors: Xiaoxi Li, Amy Hui Mei Lin, Jie Zhu, Ying He, Chen Huang, Ling Chen, Lin Li
    Abstract:

    Plasticizer Migration from packaging films to foods can raise health concerns especially when foods are heated in microwaves with their packaging. To inhibit the Plasticizer Migration, starch-based films were prepared by controlling the micro-structure of esterified starch films with various degrees of substitution (DS), and diethyl phthalate (DEP) was added. The DEP Migration after microwave heating, and the interaction between the Plasticizer and starch molecules, and the aggregation structure of starch films at nanometer scales were investigated. The data showed that the esterified starch film with the DS of 1.81 had the lowest amount of DEP Migration compared with other films (DS 1.17, 1.42, 2.27, and 2.61). The starch films with higher DS showed increased X-ray scattering intensity with a B-type starch scattering pattern. The high DS enhanced the order and compactness in both crystalline and amorphous regions of the film, and increased the distance between crystalline regions. In addition to the change in its aggregation structure, the increase of DS weakened intermolecular interaction between starch molecules, but increased the interaction between DEP and starch-ester molecules. Our approach offered a balance of structural integrity and intermolecular interaction. Plasticizer Migration was successfully reduced by controlling the DS of esterified starch film with a strong interaction between DEP and starch-ester molecules, better organized crystalline structure, and more compact and better ordered micro-region aggregation structures with suitable distance between them.

A Jayakrishnan - One of the best experts on this subject based on the ideXlab platform.

  • photocross linking of dithiocarbamate substituted pvc reduces Plasticizer Migration
    Polymer, 1998
    Co-Authors: S Lakshmi, A Jayakrishnan
    Abstract:

    Medical grade poly(vinyl chloride) (PVC) sheets and tubes were surface modified by nucleophilic substitution of chlorine atoms of PVC by photoactive N,N-diethyl dithiocarbamate (DTC) in aqueous media in the presence of a suitable phase transfer catalyst (PTC) at 55°C. The modified surface was cross-linked by irradiation with u.v. light in an attempt to create a barrier for the diffusion of the Plasticizer di-(2-ethylhexyl phthalate) (DEHP). Of the various PTCs examined for the reaction, tetrabutyl ammonium salts were found to be very effective, whereas crown ethers such as 18-crown-6 was least effective. The effect of concentration of PTC and DTC, time of reaction and irradiation dose on the extent of Plasticizer Migration was examined in petroleum ether for various periods of time at 30°C. The Migration of DEHP from PVC modified under optimum conditions was less than 5% in 120 h, whereas the unmodified PVC lost virtually all its Plasticizer ( > 30%) during the same period. Determination of the stress-strain properties of modified PVC sheets showed a reduction of approximately 30%. However, the values were still within the range prescribed for vinyl chloride plastics used for medical applications.

  • phase transfer catalysed surface modification of plasticized poly vinyl chloride in aqueous media to retard Plasticizer Migration
    Polymer, 1996
    Co-Authors: A Jayakrishnan, M C Sunny
    Abstract:

    Abstract Plasticized poly(vinyl chloride) (PVC) sheets were surface modified by nucleophilic substitution of chlorine by azide in aqueous media under phase transfer conditions. PVC was reacted with a 40% solution of sodium azide in water using tetrabutyl ammonium bromide as the phase transfer catalyst. The reaction was conducted at temperatures ranging from 50 to 80°C for various periods of time (1–4 h). The azidated PVC surface was then irradiated using u.v. light with a 125 W lamp for various time periods to crosslink the surface. Migration of the Plasticizer di-(2-ethylhexyl phthalate) from surface modified and unmodified PVC was examined in a potential organic extractant such as hexane. It was found that considerable reduction in the Migration of the Plasticizer could be achieved by this technique depending on the extent of azidation of the PVC surface and the irradiation dose. Determination of the stress/strain properties of PVC sheets before and after modification showed that there was around 30% reduction in these properties after surface modification. However, the values were still much above the minimum prescribed for vinyl chloride polymers used in biomedical applications.

  • photocrosslinking of azidated poly vinyl chloride coated onto plasticized pvc surface route to containing Plasticizer Migration
    Journal of Applied Polymer Science, 1995
    Co-Authors: A Jayakrishnan, M C Sunny, Mini N Rajan
    Abstract:

    The Migration of phthalate esters which are commonly employed for plasticizing poly(vinyl chloride) (PVC) is a significant problem in PVC-based medical devices as well as in packaging used for food stuffs and pharmaceuticals. Medical-grade PVC resin was treated with sodium azide in dimethylformamide (DMF) to prepare the azide polymer. The polymeric azide was coated onto the surface of plasticized PVC sheets by dipping in a solution of the polymer in tetrahydrofuran (THF). Crosslinking of the azide polymer was accomplished by irradiating the surface using a 125 W UV lamp for various lengths of time. Migration of the Plasticizer di 2-(ethylhexyl phthalate) (DEHP) from coated and uncoated samples was examined in n-hexane at 30°C. It was found that 50–80% reduction in Migration of DEHP could be effected from plasticized PVC in comparison with the controls in 72 h by this technique depending on the concentration of the coating solution, coating thickness, azide concentration, and irradiation dose. © 1995 John Wiley & Sons, Inc.

  • radiation grafting of hydrophilic monomers on to plasticized poly vinyl chloride sheets ii Migration behaviour of the Plasticizer from n vinyl pyrrolidone grafted sheets
    Biomaterials, 1991
    Co-Authors: Kalliyana V Krishnan, A Jayakrishnan, Joseph D Francis
    Abstract:

    The grafting of N-vinyl pyrrolidone, a hydrophilic monomer, on to flexible poly(vinyl chloride) sheets used in medical applications using ionizing radiation from a 60Co source was studied. The graft yield was found to increase linearly with monomer concentration and also with increasing radiation doses. The Migration of the Plasticizer di-(2-ethylhexyl)phthalate into a strong organic extractant such as n-hexane was studied at different time intervals for different grafted systems of poly(viny) chloride) at 30°C. The results indicated a drastic reduction in the leaching of the Plasticizer from grafted systems versus ungrafted controls. Incorporation of ethylene dimethacrylate cross-linker during grafting did not seem to affect the graft yield considerably but appeared to further reduce the Plasticizer Migration. Surface energy calculations of the grafted samples indicate that the surfaces are highly hydrophilic compared to ungrafted poly(viny) chloride) and the polar and dispersion components tend to vary with increasing cross-linker concentration.

Ling Chen - One of the best experts on this subject based on the ideXlab platform.

  • effect of amylose amylopectin ratio of esterified starch based films on inhibition of Plasticizer Migration during microwave heating
    Food Control, 2017
    Co-Authors: Yiping Zhong, Ling Chen, Chen Huang, Siyuan Liu, Jie Zhu
    Abstract:

    Plasticizer, as a necessary processing aid in producing packaging materials, migrated into food stuffs, which caused food safety problems. In order to restraint Plasticizer Migration, the hydrophobic esterified starch-based films with different multi-scale structures were prepared by regulation the ratio of amylose and amylopectin. The influence of multi-scale structures including molecular interactions between Plasticizer and esterified starch, crystalline structure and aggregation structure on inhibition of diethyl phthalate (DEP) Migration during microwave heating was studied. As the strongest molecular interactions between starch and DEP, the amount of Plasticizer Migration in waxy film was lower than that of G50 film and G80 film. Even the largest size of micro-ordered region impeded the DEP movement in G50 film, the serious further amorphization in G50 film amorphous region in microwave process and weaker molecular interactions led to higher DEP Migration compared with that of waxy film. The amount of DEP Migration in G80 film were the largest which resulted from weaker molecular interactions, damaged crystalline structure during microwave process and the smallest size of micro-ordered region. This study provided a new method to control DEP Migration which favored the application of esterified starch-based biodegradable material for food packaging.

  • Inhibition of Plasticizer Migration from packaging to foods during microwave heating by controlling the esterified starch film structure
    Food Control, 2016
    Co-Authors: Xiaoxi Li, Amy Hui Mei Lin, Jie Zhu, Ying He, Chen Huang, Ling Chen, Lin Li
    Abstract:

    Plasticizer Migration from packaging films to foods can raise health concerns especially when foods are heated in microwaves with their packaging. To inhibit the Plasticizer Migration, starch-based films were prepared by controlling the micro-structure of esterified starch films with various degrees of substitution (DS), and diethyl phthalate (DEP) was added. The DEP Migration after microwave heating, and the interaction between the Plasticizer and starch molecules, and the aggregation structure of starch films at nanometer scales were investigated. The data showed that the esterified starch film with the DS of 1.81 had the lowest amount of DEP Migration compared with other films (DS 1.17, 1.42, 2.27, and 2.61). The starch films with higher DS showed increased X-ray scattering intensity with a B-type starch scattering pattern. The high DS enhanced the order and compactness in both crystalline and amorphous regions of the film, and increased the distance between crystalline regions. In addition to the change in its aggregation structure, the increase of DS weakened intermolecular interaction between starch molecules, but increased the interaction between DEP and starch-ester molecules. Our approach offered a balance of structural integrity and intermolecular interaction. Plasticizer Migration was successfully reduced by controlling the DS of esterified starch film with a strong interaction between DEP and starch-ester molecules, better organized crystalline structure, and more compact and better ordered micro-region aggregation structures with suitable distance between them.

  • structural changes and triacetin Migration of starch acetate film contacting with distilled water as food simulant
    Carbohydrate Polymers, 2014
    Co-Authors: Jie Zhu, Chen Huang, Ling Chen
    Abstract:

    This work studied the structural changes and the Migration of triacetin Plasticizer in starch acetate films in the presence of distilled water as food simulant. Fourier-transform infrared spectroscopy result showed that the macromolecular interaction was enhanced to form compact aggregation of amorphous chains. The characterization of aggregation structures via wide and small angle X-ray scattering techniques indicated that the orderly microregion was compressed and the crystallites inside were "squeezed" to form interference and further aggregation. The compact aggregation structures restricted the mobility of macromolecules, triacetin and water molecules. The overall kinetic and the diffusion model analysis manifested that Fick's second law was the predominant mechanism for the short-term Migration of triacetin. The increasing relaxation within film matrix caused the subsequent Migration to deviate from Fick's law. The safe and reasonable application of the starch-based materials with restrained Plasticizer Migration could be accomplished by controlling the molecular interaction and aggregation structures.

  • structural changes and Plasticizer Migration of starch based food packaging material contacting with milk during microwave heating
    Food Control, 2014
    Co-Authors: Chen Huang, Jie Zhu, Ling Chen
    Abstract:

    Abstract The effect of microwave treatment on the Plasticizer Migration and the changes in multi-scale structures of starch ester films for food packaging were evaluated, and the relationship between these structural changes and Plasticizer Migration was revealed. The Plasticizer Migration from the starch ester film to the milk system was accelerated during microwave heating compared with during simple immersion at 30 °C without microwave. After microwave heating, the water and/or fat molecules of the milk system rapidly permeated the film interface to enlarge the interchain spaces. The Plasticizer molecules distributed near the boundary more readily migrated out than those located in the matrix interior. The changes in the Plasticizer/starch ester interaction and film structures weakened the stability of the ether bond both in the Plasticizer and starch ester molecules. The crystalline structure of the film was changed with a certain degree of destruction and the relevant interplanar spacing was decreased. The milk permeation into the amorphous region of the film impeded the shrinkage and aggregation of amorphous starch ester chains and even enlarged the inter-chain distances in this region. However, the ordered microaggregations were shrunk with reduced polydisperse size distribution. In consequence, the aggregation structure showed less restriction to the activated Plasticizer molecules as a result of microwave treatment. These structural changes, including the expanded amorphous region and shrunk ordered microregions, could be the reason for the greater Plasticizer Migration during the microwave treatment. This knowledge will help us in further designing the starch-based materials with restrained Plasticizer Migration by controlling the molecular interaction, crystalline structure and ordered aggregation structure within the film matrix for safe and reasonable application of this type of packaging materials.

Chen Huang - One of the best experts on this subject based on the ideXlab platform.

  • effect of amylose amylopectin ratio of esterified starch based films on inhibition of Plasticizer Migration during microwave heating
    Food Control, 2017
    Co-Authors: Yiping Zhong, Ling Chen, Chen Huang, Siyuan Liu, Jie Zhu
    Abstract:

    Plasticizer, as a necessary processing aid in producing packaging materials, migrated into food stuffs, which caused food safety problems. In order to restraint Plasticizer Migration, the hydrophobic esterified starch-based films with different multi-scale structures were prepared by regulation the ratio of amylose and amylopectin. The influence of multi-scale structures including molecular interactions between Plasticizer and esterified starch, crystalline structure and aggregation structure on inhibition of diethyl phthalate (DEP) Migration during microwave heating was studied. As the strongest molecular interactions between starch and DEP, the amount of Plasticizer Migration in waxy film was lower than that of G50 film and G80 film. Even the largest size of micro-ordered region impeded the DEP movement in G50 film, the serious further amorphization in G50 film amorphous region in microwave process and weaker molecular interactions led to higher DEP Migration compared with that of waxy film. The amount of DEP Migration in G80 film were the largest which resulted from weaker molecular interactions, damaged crystalline structure during microwave process and the smallest size of micro-ordered region. This study provided a new method to control DEP Migration which favored the application of esterified starch-based biodegradable material for food packaging.

  • Inhibition of Plasticizer Migration from packaging to foods during microwave heating by controlling the esterified starch film structure
    Food Control, 2016
    Co-Authors: Xiaoxi Li, Amy Hui Mei Lin, Jie Zhu, Ying He, Chen Huang, Ling Chen, Lin Li
    Abstract:

    Plasticizer Migration from packaging films to foods can raise health concerns especially when foods are heated in microwaves with their packaging. To inhibit the Plasticizer Migration, starch-based films were prepared by controlling the micro-structure of esterified starch films with various degrees of substitution (DS), and diethyl phthalate (DEP) was added. The DEP Migration after microwave heating, and the interaction between the Plasticizer and starch molecules, and the aggregation structure of starch films at nanometer scales were investigated. The data showed that the esterified starch film with the DS of 1.81 had the lowest amount of DEP Migration compared with other films (DS 1.17, 1.42, 2.27, and 2.61). The starch films with higher DS showed increased X-ray scattering intensity with a B-type starch scattering pattern. The high DS enhanced the order and compactness in both crystalline and amorphous regions of the film, and increased the distance between crystalline regions. In addition to the change in its aggregation structure, the increase of DS weakened intermolecular interaction between starch molecules, but increased the interaction between DEP and starch-ester molecules. Our approach offered a balance of structural integrity and intermolecular interaction. Plasticizer Migration was successfully reduced by controlling the DS of esterified starch film with a strong interaction between DEP and starch-ester molecules, better organized crystalline structure, and more compact and better ordered micro-region aggregation structures with suitable distance between them.

  • structural changes and triacetin Migration of starch acetate film contacting with distilled water as food simulant
    Carbohydrate Polymers, 2014
    Co-Authors: Jie Zhu, Chen Huang, Ling Chen
    Abstract:

    This work studied the structural changes and the Migration of triacetin Plasticizer in starch acetate films in the presence of distilled water as food simulant. Fourier-transform infrared spectroscopy result showed that the macromolecular interaction was enhanced to form compact aggregation of amorphous chains. The characterization of aggregation structures via wide and small angle X-ray scattering techniques indicated that the orderly microregion was compressed and the crystallites inside were "squeezed" to form interference and further aggregation. The compact aggregation structures restricted the mobility of macromolecules, triacetin and water molecules. The overall kinetic and the diffusion model analysis manifested that Fick's second law was the predominant mechanism for the short-term Migration of triacetin. The increasing relaxation within film matrix caused the subsequent Migration to deviate from Fick's law. The safe and reasonable application of the starch-based materials with restrained Plasticizer Migration could be accomplished by controlling the molecular interaction and aggregation structures.

  • structural changes and Plasticizer Migration of starch based food packaging material contacting with milk during microwave heating
    Food Control, 2014
    Co-Authors: Chen Huang, Jie Zhu, Ling Chen
    Abstract:

    Abstract The effect of microwave treatment on the Plasticizer Migration and the changes in multi-scale structures of starch ester films for food packaging were evaluated, and the relationship between these structural changes and Plasticizer Migration was revealed. The Plasticizer Migration from the starch ester film to the milk system was accelerated during microwave heating compared with during simple immersion at 30 °C without microwave. After microwave heating, the water and/or fat molecules of the milk system rapidly permeated the film interface to enlarge the interchain spaces. The Plasticizer molecules distributed near the boundary more readily migrated out than those located in the matrix interior. The changes in the Plasticizer/starch ester interaction and film structures weakened the stability of the ether bond both in the Plasticizer and starch ester molecules. The crystalline structure of the film was changed with a certain degree of destruction and the relevant interplanar spacing was decreased. The milk permeation into the amorphous region of the film impeded the shrinkage and aggregation of amorphous starch ester chains and even enlarged the inter-chain distances in this region. However, the ordered microaggregations were shrunk with reduced polydisperse size distribution. In consequence, the aggregation structure showed less restriction to the activated Plasticizer molecules as a result of microwave treatment. These structural changes, including the expanded amorphous region and shrunk ordered microregions, could be the reason for the greater Plasticizer Migration during the microwave treatment. This knowledge will help us in further designing the starch-based materials with restrained Plasticizer Migration by controlling the molecular interaction, crystalline structure and ordered aggregation structure within the film matrix for safe and reasonable application of this type of packaging materials.

Ulf W Gedde - One of the best experts on this subject based on the ideXlab platform.

  • Plasticizer Migration from pvc cable insulation the challenges of extrapolation methods
    Polymer Degradation and Stability, 2014
    Co-Authors: Erik Linde, Ulf W Gedde
    Abstract:

    A single strand PVC-P insulation including an internal metal conductor removed from the jacketed assemblies of a signal cable showed brittleness after 30 years service at 25 ± 3 °C in air. The PVC compound contained diisodecyl phthalate (DIDP), di(2-ethylhexyl) phthalate (DEHP) and a sizeable fraction of filler. Single strand insulation samples with internal metal conductor were aged in air at elevated temperatures for different periods of time after which the strain at break, the Young's modulus and the Plasticizer content were assessed by tensile testing and liquid chromatography. Isothermal evaporation rates from pristine DIDP and DEHP and solutions of the two Plasticizers were obtained by thermogravimetry. Data for Young's modulus, strain at break and Plasticizer contents were extrapolated to service temperature using two different extrapolation methods, Arrhenius extrapolation (constant activation energy) and a method based on models by Langmuir, Clausius–Clapeyron and Kirchhoff. These methods assume that evaporation of Plasticizers to the surrounding gas phase is the dominant deterioration mechanism. Both methods predicted only a minor decrease in Plasticizer content after 30 years of ageing at 28 °C and thus a material with adequate mechanical properties. Liquid chromatography showed that the single strand cable samples contained a very low DIDP content (4 wt.%) and an anomalously high DEHP content; a finding that cannot be explained by the expected evaporative loss mechanism. It is suggested that DIDP was efficiently extracted by contact with a DEHP-rich interface at the insulation surface, a process which is active during plant operation, but could not be simulated by controlled laboratory accelerated ageing studies.

  • Plasticizer Migration from pvc cable insulation a case study testing different extrapolation methods
    2013
    Co-Authors: Erik Linde, Ulf W Gedde
    Abstract:

    Plasticizer Migration from PVC cable insulation - a case study testing different extrapolation methods