A Study of Biodegradation Behaviour of Dextrin Grafted Polyethylene by Soil Burial Method

Present studies report the biodegradation of dextrin grafted polyethylene (PE), successfully synthesized by graft co-polymerization method using benzoyl peroxide as the radical initiator. Biodegradable behaviour of the grafted PE was ascertained by soil burial test. Percent weight loss was measured as a function of number of days and it was observed that percent weight loss increased with increasing number of days. To further substantiate the degradation, microanalysis of the soil containing the samples was carried out. An increase in the colonies of microorganisms was observed with increasing number of days. The hydrolysis of the samples taken out from the soil after a specified number of days also corroborated the findings revealing continuous loss of weight. Effect of degradation of the grafted samples on the growth of plants (wheat and soybean) was studied and it was observed that the products of degradation are not harmful to the growth of the plants.     

Evaluation of reinforcement on the mechanical behavior of partially bonded fiber/matrix interface

This paper aims at introducing a new natural composite used as soil stabilizer with particular application in geotechnical engineering. The fibers introduced in the present study could be used as effective soil reinforcement. This research proves the feasibility of the use of modified jute/polypropylene in lime and cement composites and studies their effects on the tensile and compressive strength of the matrix. In general, the optimal mechanical performance of natural composites and durability depends on the optimization of the interfacial bond between natural fiber and matrix. Since the fibers and matrices are chemically different, strong adhesion at their interfaces is needed for an effective transfer of stress and bond distribution throughout an interface. In this paper a theoretical approach for the identification of elastic modulus in composite interfaces is proposed in detail with a reasonable error. The theoretical approach is based on the method using a sum of least squares criterion. The approach is applied through optimization techniques, using analytical sensitivities and correlating adhesion with Young's modulus. The validity and potentiality of the proposed technique is discussed and the results demonstrated the versatility, accuracy, and efficiency of the presented approach. The applied method also appears to be a simple way of predicting the modulus of elasticity in composite interfaces. This leads to a discussion of the most promising stabilization methods for soil reinforcement and the outlook for the future.     

Applications of expanded polystyrene (EPS) beads and polyamide 66 in civil engineering,Part Two: Stabilization of clayey sand by lime/polyamide-66

While lime is most commonly used as stabilizing agent for clayey sands, this stability can be significantly improved with composition of lime containing polyamide-66 strips. Lime reacts chemically with fine grained material through a process termed cation exchange. The lime creates a surplus of Ca²⁺ cations that tend to replace monovalent cations. This cation exchange process results in the clayey sand becoming much less susceptible to moisture (i.e. more stable in terms of volume change). Polyamide-66 does not react chemically with the materials being stabilized but increases the particle reinforcement. Hence, we are presenting two broad areas of stabilization mechanisms in this work — chemical and mechanical stabilization. Polyamide-66 is an engineering plastic with a distinguished role in this category of polymers due to its high chemical and mechanical resistance. This paper presents a comparative study with our previous published works on this subject. The mechanisms involved in stabilization, the methodologies applied, the evaluation criteria, and the resulting data have been appraised and interpreted.     

单宁聚氨酯土壤微生物降解研究

采用凝胶渗透色谱仪(GPC)、傅立叶变换红外光谱仪(FT-IR)和电子扫描显微镜(SEM)等实验手段,考察了单宁聚氨酯(WT-PU)在土壤微生物降解前后的化学结构与微观形态的变化,而作为比较用的模型化合物(TMP-PU)在同样的条件下几乎没有变化。结果表明单宁一这交联点在PU整体中以无规降解的方式优先降解,在整个降解过程中,不仅伴随着PU硬段的氢键减弱,软段的氢键也同样有相当的减弱。