Packaging‐related properties of protein‐ and chitosan‐coated paper
ABSTRACT The mechanical and gas-barrier properties of paper and paperboard coated with chitosan–acetic acid salt (chitosan), whey protein isolate, whey protein concentrate and wheat gluten protein were studied. Paper sheets were solution-coated using a hand applicator. In addition, bi-layer composites of wheat gluten and paper or paperboard were produced by compression moulding, and the chitosan solution was also applied on paperboard using curtain coating. Young's modulus, fracture stress, fracture strain, tearing strength, air permeance and oxygen permeability were assessed. The mechanical and air permeance measurements of solution-coated paper showed that chitosan was the most effective coating on a coat weight basis. This was due to its high viscosity, which limited the degree of penetration into the paper. The proteins, however, also enhanced the strength and toughness of the paper. Compression-moulded wheat gluten/paper or paperboard, as well as curtain-coated chitosan paperboard laminates, showed oxygen barrier properties comparable to those of paper and paperboard coated with commercial barrier materials. None of the composites could be delaminated without fibre rupture, indicating good adhesion between the coatings and the substrates. Copyright © 2005 John Wiley & Sons, Ltd.
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ABSTRACT: This study presents a comparison of the mechanical and barrier properties of papers coated with microfibrillated cellulose (MFC) by two different coating processes: (i) bar coating and (ii) size press. Due to the high water content of MFC, water-treated papers were taken as references to highlight the effects of MFC on the properties of papers. Structural, mechanical and barrier properties of the ensued materials were performed respectively with SEM, tensile and stiffness testers, and air and oxygen permeability equipments. The properties of the water-treated papers were considerably damaged compared to those of the base paper that underlined the negative impact of both coating processes on the papers structure. With MFC, the air barrier and the bending stiffness were considerably improved (+90 and +50 % respectively), especially when the bar coating was used, i.e. with 7 g m−2 of MFC. Size press was indeed not able to considerably improve papers properties as the MFC coat weight barely reached 4 g m−2 resulting from ten successive MFC layers.Journal of Materials Science 04/2014; 49(7). · 2.16 Impact Factor
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ABSTRACT: To improve the availability of vessel grafts for allotransplantation, the current experimental study was designed to first investigate the function of vessels obtained from non-heartbeating donor rats at various time points postmortem; second, to assess the sensitivity of vessels recovered after circulatory arrest toward prolonged cold storage; and third, to determine vessel function following cold storage with antimicrobial additives. We investigated vessel tone development and endothelium-dependent and endothelium-independent relaxations in a Mulvany myograph of aorta and saphenous artery sampled up to 24 hours after circulatory arrest. Additionally, tissue reductive capacity and lactate dehydrogenase release were measured. Vessels recovered 2 hours postmortem showed similar results as controls recovered without delay. Vessels recovered 6 hours or more after circulatory arrest showed reduced vessel tone development (ie, aorta): response to potassium <15% and response to norepinephrine <25% of vessels recovered without delay; A. saphena response to potassium: <12% and response to norepinephrine <10% of control vessels recovered without delay. All vessels recovered after circulatory arrest showed a similar cold storage sensitivity as controls, with exception of a decreased endothelial function of A. saphena harvested 6 hours postmortem (one-third response of non-stored control vessels). Treatment of vessels recovered immediately or after circulatory arrest with gentamycin, piperacillin, and metronidazole as additives to the optimized cold storage solution did not alter vessel function. Flucloxacillin as a cold storage additive reduced vessel tone development in aorta but not in A. saphena. Addition of amphotericin B to the storage solution completely abolished any vessel function and impaired tissue reductive capacity despite presence of radical scavengers. The use of vessels from non-heartbeating donors in general and subsequent prolonged cold storage seems feasible when vessels are recovered within 2 hours. The use of antibiotics needs to be carefully assessed for each intended-to-use tissue. For vessels tested, a combination of gentamycin, piperacillin, and metronidazole supported the maintenance of vessel function.Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 09/2011; 54(6):1769-77. · 3.52 Impact Factor
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ABSTRACT: The effects of glycerol concentration and coating weight on biopolymer-coated paper properties were investigated using response surface methodology. Tests were run on the coated papers to determine water vapor barrier and mechanical properties. Coating weight was the most important parameter affecting water vapor permeability (WVP). Conversely, increasing coating weight led to a decrease in WVP and to an increase in tensile strength (TS) of the resulting coated papers. The papers coated with sodium caseinate (NaCAS) exhibited lower WVP values than those coated with other biopolymers. The TS of the papers coated with hydroxypropylmethylcellulose (HPMC) and chitosan was not affected by the glycerol concentration. HPMC-coated papers were higher in TS and %E than the other coated papers. For all types of coated paper, a maximum level of coating weight and level of glycerol concentration within range of 18.72–26.11% were found to be optimum for minimum WVP and maximum TS and %E.Highlights► Properties of coated papers are influenced by glycerol concentration and coating weight. ► Coating weight factor decreases water vapor permeability. ► Water vapor permeability is lowest for sodium caseinate-coated paper. ► Glycerol concentration has a positive influence on elongation values. ► Optimization of responses is performed by desirability function method.Carbohydrate Polymers 01/2011; 86(2):1063-1072. · 3.48 Impact Factor