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The influence of type and content of modified montmorillonite (MMT) clay and amount of compatibilizing agent on physical-mechanical properties of polypropylene (PP)/organoclay films were studied. An unexpected decrease in tensile elastic modulus and yield stress was observed, and a striking drop in film density. SEM micrographs showed film microcavitation at polymer/clay interfaces. Experimental design analysis indicated that the most important parameter was the organoclay content: the higher the proportion of MMT, the lower the values of film properties. The addition of compatibilizer promoted an improvement in these film properties, probably due to the formation of less porous film. [ABSTRACT FROM AUTHOR]

In this study, the effect of heat treatment on barrier and functionality of polyolefin-coated papers was investigated. The aim was to find the optimal improvements on barrier without losing the applicability of the materials due to physical damages. The results of the study proved considerable improvement in barrier characteristics of the structures. Both water vapor and oxygen transmission rates of LDPE-coatings decreased linearly following the set-temperature until 200°C. At this point, the treatment caused a continuing decrease in oxygen transmission achieving 10 × lower transmission levels than the untreated structure, whereas moisture transport faced corresponding but lower increase. This was considered to be caused by the difference in diameter of the H2O and O2 molecules; the smaller water molecules are able to penetrate between spherulites, whose size increased due to higher treatment temperature followed by cooling. [ABSTRACT FROM AUTHOR]

World demand for paper has increased at an average annual rate of 4.7% over the past 40 years. Although future growth will reduce to 2–3% the existing wood resources may be inadequate to meet this growing demand for paper especially in the Asia-Pacific region and Eastern Europe. In addition, logging is coming under increasing pressure from environmentalists concerned about habitat destruction and other longer-term impacts of forest harvesting. It is, therefore, necessary to consider alternative fiber sources to meet the possible shortfall of wood fiber for papermaking. Suitable nonwood fibers are abundantly available in many countries and are the major source of fiber for papermaking in some developing nations. [ABSTRACT FROM AUTHOR]

Clay particles added to fibers are not easily retained in the forming sheet so the mechanical properties of paper suffer. Modified starches and polyacrylamide (PAM) are used as retention aids for clay and strengthening agents. Modified starch is a better strengthening agent and retention aid than is polyacrylamide. The high retention of clay can be obtained by using modified starch and PAM. Heated kaolin at 800°C is retained better than unheated kaolin. [ABSTRACT FROM AUTHOR]

In this study, an attempt is made to understand the chemical and morphological characteristics of Malaysian cultivated kenaf fractions (bast, core, and whole stem). Results based on morphologyand chemical analysis indicate that bast and core fiber fractions in the kenaf are significantly different, although the chemical composition of kenaf is quite similar to the woody mass. In the case of whole stem fibers, it is concluded that the effective length of fibers from the whole stem is reasonably good for the purpose of making printing papers. [ABSTRACT FROM AUTHOR]

Maize starch was oxidized with sodium hypochlorite and hydrogen peroxide. Carboxyl content of oxidized starch were determined. Carboxyl content of starch oxidized with hydrogen peroxide is greater than that oxidized with hypochlorite. The maximum carboxyl content was obtained at pH 11 for 2 h by using hydrogen peroxide. On addition of oxidized starch to wood pulp shows great improvement in mechanical and physical properties of wood paper. Oxidized starch can be used as a good retention aid for kaolin. [ABSTRACT FROM AUTHOR]

Recently, an environmental criteria was required for every product and process. The great amount of pollution caused by the paper and cellulose industry effluents, especially those produced from nonwood fibrous materials, e.g., rice straw and bagasse. Using new technologies or redesigning products to meet new environments criteria is necessary. The production of cellulose by microorganisms is considered as one of the most beneficial sources for environment requirements. Microbial polysaccharides are valuable commodities, since they display many useful properties and can be produced in large quantities. This article reviews previous research on the biosynthesis of bacterial cellulose, structural features, properties, as well as potential applications as new industrial materials, i.e., paper industry, wastes treatment, sewage purification, food, medicine, etc. Suggestions for an economic production process for bacterial cellulose and cellulose derivatives also were reported. [ABSTRACT FROM AUTHOR]