Effect of nano TiO 2 on the cellular structure and mechanical properties of wood flour/polypropylene composite foams via mold‐opening foam injection molding

Nanotechnology in wood science: Innovations and applications

Application of nanomaterials is gaining tremendous interest in the field of wood science and technology for value addition and enhancing performance of wood and wood-based composites. This review focuses on the use of nanomaterials in improving the properties of wood and wood-based materials and protecting them from weathering, biodegradation, and other deteriorating agents. UV-resistant, self-cleaning (superhydrophobic) surfaces with anti-microbial properties have been developed using the extraordinary features of nanomaterials. Scratch-resistant nano-coatings also improve durability and aesthetic appeal of wood. Moreover, nanomaterials have been used as wood preservatives for increasing the resistance against wood deteriorating agents such as fungi, termites and borers. Wood can be made more resistant to ignition and slower to burn by introducing nano-clays or nanoparticles of metal-oxides. The use of nanocellulose and lignin nanoparticles in wood-based products has attracted huge interest in developing novel materials with improved properties. Nanocellulose and lignin nanoparticles derived/synthesized from woody biomass can enhance the mechanical properties such as strength and stiffness and impart additional functionalities to wood-based products. Cellulose nano-fibres/crystals find application in wide areas of materials science like reinforcement for composites. Incorporation of nanomaterials in resin has been used to enhance specific properties of wood-based composites. This review paper highlights some of the advancements in the use of nanotechnology in wood science, and its potential impact on the industry.

A review of environmental friendly green composites: production methods, current progresses, and challenges

The growing concern about environmental damage and the inability to meet the demand for more versatile, environmentally friendly materials has sparked increasing interest in polymer composites derived from renewable and biodegradable plant-based materials, mainly from forests. These composites are mostly referred to as "green" and they can be widely employed in many industrial applications. Green composites are less harmful to the environment and could be potential substitutes for petroleum-based polymeric materials. It is helpful to limit usage of fossil oil assets by developing biopolymer matrices such as cellulose-reinforced biocomposites using renewable assets such as plant oils, carbohydrates, and proteins. This paper focuses on green composites processing utilizing a variety of naturally available resources, sustainable materials which are not detrimental to the environment, new scientific signs of progress in achieving green sustainable development, as well as nanotechnology and its environmental consequences. Additionally, the environmental impacts of different composite materials are examined in this paper, along with their production from eco-friendly materials. Moreover, the manufacturing aspects of green composites and some concerns related to their production are also discussed. The merits of green composite materials and valid reasons why they are a valuable substitute for the traditionally used composite materials are also covered.

Oscillating light engine realized by photothermal solvent evaporation

Continuous mechanical work output can be generated by using combustion engines and electric motors, as well as actuators, through on/off control via external stimuli. Solar energy has been used to generate electricity and heat in human daily life; however, the direct conversion of solar energy to continuous mechanical work has not been realized. In this work, a solar engine is developed using an oscillating actuator, which is realized through an alternating volume decrease of each side of a polypropylene/carbon black polymer film induced by photothermal-derived solvent evaporation. The anisotropic solvent evaporation and fast gradient diffusion in the polymer film sustains oscillating bending actuation under the illumination of divergent light. This light-driven oscillator shows excellent oscillation performance, excellent loading capability, and high energy conversion efficiency, and it can never stop with solvent supply. The oscillator can cyclically lift up a load and output work, exhibiting a maximum specific work of 30.9 × 10⁻⁵ J g⁻¹ and a maximum specific power of 15.4 × 10⁻⁵ W g⁻¹ under infrared light. This work can inspire the development of autonomous devices and provide a design strategy for solar engines.

Developing an oscillating actuator that can directly convert solar energy into mechanical energy is highly desirable. Here, authors report a solvent-assisted light-driven oscillator by porous film that achieves excellent oscillating actuation performance and can even oscillate by carrying a load under light irradiation.