Roadmap of Effects of Biowaste-Synthesized Carbon Nanomaterials on Carbon Nano-Reinforced Composites

Sustainable growth can be achieved by recycling waste material into useful resources without affecting the natural ecosystem. Among all nanomaterials, carbon nanomaterials from biowaste are used for various applications. The pyrolysis process is one of the eco-friendly ways for synthesizing such carbon nanomaterials. Recently, polymer nanocomposites (PNCs) filled with biowaste-based carbon nanomaterials attracted a lot of attention due to their enhanced mechanical properties. A variety of polymers, such as thermoplastics, thermosetting polymers, elastomers, and their blends, can be used in the formation of composite materials. This review summarizes the synthesis of carbon nanomaterials, polymer nanocomposites, and mechanical properties of PNCs. The review also focuses on various biowaste-based precursors, their nanoproperties, and turning them into proper composites. PNCs show improved mechanical properties by varying the loading percentages of carbon nanomaterials, which are vital for many defence- and aerospace-related industries. Different synthesis processes are used to achieve enhanced ultimate tensile strength and modulus. The present review summarizes the last 5 years’ work in detail on these PNCs and their applications.

Technologies for the Production of Machine-Building Composite Polymer Materials and Coatings Working in Contact With Raw Cotton

Based on numerous analyses of the research results, a technology was developed for obtaining the developed composite thermosetting polymer coatings based on thermosetting polymers-epoxy oligomers ED-20, FAED-20 and FEIS-30 plasticizer, dibutyl phthalate, polyethylene polyamine hardener and industrial waste and organomineral ingredients, as well as a technology for applying antifriction-strength composite polymer coatings for machine-building purposes on metal surfaces of products of various machines and mechanisms.

Prolonged Thermal Relaxation of the Thermosetting Polymers

The rigidity of structures made of polymer composite materials, operated at elevated temperatures, is mainly determined by the residual rigidity of the polymer binder (which is very sensitive to elevated temperatures); therefore, the study of ways to increase the rigidity of polymer materials under heating (including prolonged heating) is relevant. In the previous research, cured thermosetting polymer structure’s non-stability, especially under heating, is determined by its supra-molecular structure domain’s conglomerate character and the high entropy of such structures. The polymer elasticity modeling proved the significance of the entropy factor and layer (EPL) model application. The prolonged heating makes it possible to release adsorptive inter-layer bonds and volatile groups. As a result, the polymer structure is changing, and inner stress relaxation occurs due to this thermo-process, called thermo-relaxation. The present study suggests researching thermo-relaxation’s influence on polymers’ deformability under load and heating. The research results prove the significant polymer structure modification due to thermo-relaxation, with the polymer entropy parameter decreasing, the glassing onset temperature point (Tg) increasing by 1.3–1.7 times, and the modulus of elasticity under heating increasing by 1.5–2 times.

Generation of Continuous Toolpaths for Additive Manufacturing Using Implicit Slicing

The generation of footpaths for additive manufacturing (AM), a process commonly known as “slicing,” has a strong impact on the performance of both the associated hardware systems and the resulting objects. Available slicers invariably produce discontinuous tootpaths, featuring jumps or so-catted “travel moves” during which the deposition of material or/and energy must be hatted. For AM processes using slowly solidifying feedstock materials, such as thermosetting polymers or cementitious mixtures such as concrete, these tootpath discontinuities are highly undesirable due to the artifacts they generate. This renders existing sticers difficult to use in such applications, and presents a road-block to the adoption of AM for such material systems. In the present work, this difficulty is addressed by the development of a simple geometric criterion for the existence of continuous tool-paths that are capable of producing a specified input geometry. This development is based on the principles of morphological geometric analysis and graph theory. It is shown that, for any geometric feature with a characteristic thickness at least twice the extrusion width, a continuous toolpath exists. Furthermore, a general-purpose algorithm for continuous toolpath generation, for arbitrarily shaped objects satisfying this criterion, is developed and demonstrated on a representative test problem. Finally, conclusions and the path forward for the usage of this approach with existing AM systems is explored.

Cure Kinetics and Inverse Analysis of Epoxy-Amine Based Adhesive Used for Fastening Systems

Thermosetting polymers are used in building materials, for example adhesives in fastening systems. They harden in environmental conditions with a daily temperature depending on the season and location. This curing process takes hours or even days effected by the relatively low ambient temperature necessary for a fast and complete curing. As material properties depend on the degree of cure, its accurate estimation is of paramount interest and the main objective in this work. Thus, we develop an approach for modeling the curing process for epoxy based thermosetting polymers. Specifically, we perform experiments and demonstrate an inverse analysis for determining parameters in the curing model. By using calorimetry measurements and implementing an inverse analysis algorithm by using open-source packages, we obtain 10 material parameters describing the curing process. We present the methodology for two commercial, epoxy based products, where a statistical analysis provides independence of material parameters leading to the conclusion that the material equation is adequately describing the material response.

Sustainable and Ecofriendly Chemical Design of High Performance Bio-Based Thermosets for Advanced Applications

High performance thermosetting resins are targeted in many exigent applications, such as aerospace and marine fields, for the development of lightweight structural composites. Till now, these industries only rely on petroleum-based materials for their supposedly better performances. However, the latest developments in the field suggest otherwise. In fact, many reports confirmed that sustainable and ecofriendly thermosetting polymers can display similar or even better performances. Additionally, exploring alternative renewable feedstock’s to meet the ever increasing demands of these industries is an essential step towards sustainable development. Aiming to unravel the potential of these materials, the present review summarizes the most relevant chemical routes allowing the preparation of fully or partially bio-based thermosetting resins. Meanwhile, the overall performances of these exceptional materials are also compared with their petroleum-based counterparts.