Starch is one of the most common biodegradable polymers found in nature, and it is widely utilized in the food and beverage, bioplastic industry, paper industry, textile, and biofuel industries. Starch has received significant attention due to its environmental benignity, easy fabrication, relative abundance, non-toxicity, and biodegradability. However, native starch cannot be directly used due to its poor thermo-mechanical properties and higher water absorptivity. Therefore, native starch needs to be modified before its use. Major starch modification techniques include genetic, enzymatic, physical, and chemical. Among those, chemical modification techniques are widely employed in industries. This review presents comprehensive coverage of chemical starch modification techniques and genetic, enzymatic, and physical methods developed over the past few years. In addition, the current applications of chemically modified starch in the fields of packaging, adhesives, pharmaceuticals, agriculture, superabsorbent and wastewater treatment have also been discussed.

The health and environmental concerns of the usage of non-biodegradable plastics have driven efforts to explore replacing them with renewable polymers. Although starch is a vital renewable polymer, poor water resistivity and thermo-mechanical properties have limited its applications. Recently, starch/synthetic biodegradable polymer blends have captured greater attention to replace inert plastic materials; the question of ‘immiscibility’ arises during the blend preparation due to the mixing of hydrophilic starch with hydrophobic polymers. The immiscibility issue between starch and synthetic polymers impacts the water absorption, thermo-mechanical properties, and chemical stability demanded by various engineering applications. Numerous studies have been carried out to eliminate the immiscibility issues of the different components in the polymer blends while enhancing the thermo-mechanical properties. Incorporating compatibilizers into the blend mixtures has significantly reduced the particle sizes of the dispersed phase while improving the interfacial adhesion between the starch and synthetic biodegradable polymer, leading to fine and homogeneous structures. Thus, Significant improvements in thermo-mechanical and barrier properties and water resistance can be observed in the compatibilized blends. This review provides an extensive discussion on the compatibilization processes of starch and petroleum-based polymer blends.

Circular economy (CE) is an emergent concept that promotes resource circularity in multiple product systems. Modular construction (MC), an evolving construction technique, which includes an off-site manufacturing environment, increasingly supports CE strategies such as reuse due to the elevated potential for design for disassembly (DfD). Design-stage environmental assessments are paramount in aiding the early decision making of modular construction projects to successfully plan and implement DfD strategies. Research on synergising modular construction, circular economy and environmental sustainability is rare in developing economies. Thus, the current study aims to conduct a design-stage life cycle assessment of a DfD and linear versions of a modular building unit in Sri Lanka to evaluate the potential environmental benefits. The life cycle assessment results highlight that the DfD strategy has the lowest environmental impacts in all categories, with a 63% reduction in global warming potential and an approximately 90% reduction in terms of human toxicity compared to the linear version. Further, it showed the elevated potential of reuse compared to recycling practices in improving the environmental performance. Sensitivity assessment revealed that steel was the most sensitive to the change in reuse percentage among main building materials. The analysis outcomes highlight the importance of long-term thinking, architectural design creativity and industrial and technology development to uptake the CE-driven MC in the Sri Lankan context. Finally, strategies are proposed to support the CE approach in MC in developing regions. Both quantitative and qualitative outcomes provide a basis for construction industry stakeholders, academia, and policy makers to explore further and promote modular construction practices to enhance the circularity of building materials and components in developing regions.

Sustainable manufacturing is creation of manufactured products through economically-sound processes that minimize negative environmental impacts while conserving energy and natural resources. Sustainable manufacturing also enhances employee, community, and product safety. In order to adapt sustainable Manufacturing concepts, it is essential to plan and decide from a product design and development stage as it has been revealed that 80% of sustainability impacts from the product are decided in the product design and development stage. In modern day Products Design and manufacturing it is always advantages to have complete knowledge of the Life Cycle of the Product. If Life cycle information is available for the designers, it will be easy for them to take many decisions related to specially the environmental performance or eco efficiency which is one of the emerging marketing tools. Further, with the full knowledge of the product life cycle, new/existing products can be designed/redesigned based on eco-design principals or environmentally friendly manner, thereby to improve the material and energy efficiency during the manufacturing and user phases and finally will have better environmental performances. The product life cycle and Eco design are two key techniques used in Sustainable Manufacturing specially these will enable to convert any existing product or process to be competitive in the market by better environmental performances and quality while minimizing manufacturing cost beside with better environmental performances. These issues prevail mainly since there is no such systematic approach towards Product Design and Development among the many manufacturers. Since Sustainable Manufacturing Concept applicable for all major phases of the product Life cycle, it is essential to co-relate life cycle assessment outcomes with product design and development process. However, there are numerous decisions needed to take into account at different stages of product design and development process. Therefore, in this research, a decision support model is developed based on LCA and Eco Design concepts. The developed model has been validated with few existing product decision and development processes. The results shows that significant number of issues and potential improvements to the existing design and development processes can be taken from the proposed model and that will leads to many sustainability options to the whole product life cycle than what is persist presently

In this study, two types of modified cassava starch samples (MCS and MWS) prepared from commercially available native cassava starch (NCS) and native cassava starch extracted using the wet method (NWS) were investigated for the removal of Pb(II) ions from aqueous solutions. MCS and MWS samples were synthesized under acidic conditions using Pluronic 123 as the structure-directing agent and tetraethylorthosilicate (TEOS) as the chemical modifying agent. Modified starch samples were characterized using Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), X-ray Diffraction (XRD), and a nitrogen (N₂) gas adsorption–desorption analyser. MCS and MWS showed enhanced thermal stabilities upon acid hydrolysis and chemical modification. The effects of contact time and initial Pb(II) concentration were studied through batch adsorption experiments. Adsorption kinetics followed the pseudo-second-order kinetic model. The equilibrium adsorption data were analysed and compared by the Langmuir and Freundlich adsorption models. The coefficient correlation (R²) was employed as a measure of the fit. The Langmuir model fitted well with equilibrium adsorption data, giving a maximum Pb(II) adsorption capacity of 370.37 and 294.12 mg/g for MWS and MCS, respectively. Modified samples exhibited a higher desorption efficiency of over 97%. This study demonstrated that modified starch could be utilized for Pb(II) removal from industrial wastewater.