Green composites are a special class of composites in which at least one of the components is obtained from natural resources. They are an alternative to traditional composites because of their useful properties such as biodegradability, low cost, easy processability, sound insulation and recycling. Green composites, which emerge as environmentally friendly polymeric composite materials, offer techno-economic advantages in commercial and engineering applications and are among the widely dealt subjects due to the very high demand from the global market. The aim of this study is to investigate the effect of chestnut wood flour size on the mechanical properties of chestnut-wood-flour-filled vinyl ester composites. With this aim, composite specimens were produced by using vinyl ester polymer as the matrix material and chestnut wood flour in three different sizes (0–150, 150–315 and 315–400 μm) as the natural filler. In each size combination, four different matrix/filler ratios (5, 10, 15 and 20% by weight) were adopted. These mixtures were then poured into Teflon moulds to produce the test specimens. Izod impact, three-point bending, hardness and tensile strength tests were performed on the composite specimens. In addition, morphological investigations were performed on the fractured surfaces of the specimens by using scanning electron microscopy. It is concluded that composites with a small-sized chestnut wood flour as the filler have superior properties for composite applications.

A composite refers to a material composed of two or more distinct constituents with different physical or chemical properties, combined to create a new material with enhanced characteristics. Polymer matrix composites (PMCs) have garnered significant attention due to their versatile properties and wide-ranging applications. The incorporation of fillers into polymer matrices plays a crucial role in tailoring the properties of PMCs. In polymer matrix composites there can be used two different types of fillers, natural and synthetic. In this study, unsaturated polyester resin was used as thermoset matrix material. Calcite and oak wood sawdust are used as fillers. Calcite is used as a synthetic filler and oak wood sawdust is a natural filler. Also, ratios vary depending on filler types, but the total filler ratio is chosen as 20%. Composite samples were prepared by pouring the mixture into an open Teflon mould. The physical properties of the samples such as tensile, impact, density, water absorption and hardness were investigated. Images of broken surfaces were analysed by SEM. As a result of the study, it was evaluated that oak wood sawdust and calcite can be used together in polyester-based composite applications.

In this study, hybrid composites were produced by using polypropylene (PP) polymer as matrix material, and hazelnut shell (HS) and wollastonite (W) as reinforcement in different ratios. Hazelnut shell flour (HSF) and wollastonite reinforced polypropylene mixtures were modified with poly(styrene-b-ethylene-co-butylene-b-styrene) (SEBS) triblock copolymer and maleic anhydride grafted SEBS (SEBS-g-MA). Wear properties of the hybrid composites were investigated as a function of elastomeric component. First, the reference hybrid composites were prepared from PP and W + HSF mixtures in the ratio of 80/10+10 by weight through extrusion method. SEBS and SEBS-g-MA modified hybrid composites (%, by weight ratios - 3, 6, 9) were then prepared by using these reference mixtures. The goal of this study is to investigate the effect of elastomeric modifications on the wear properties of the hybrid composites. Wear test samples prepared out of those mixtures by injection molding. In order to avoid any degradation due to the temperature sensitivity of the hazelnut shell, temperatures were kept close to lower limits during extrusion processing. Wear features of the samples were investigated by using an abrasion tester. Scanning electron microscopy was used for analyzing morphological features of the worn surfaces. It was found that SEBS and SEBS-g-MA modifications resulted in the reduction of the weight loss.

Tarımsal atıkların kullanımı, çevresel hassasiyetlerin artması ve atıkların ekonomiye kazandırılması gibi duyarlılıklardan dolayı gün geçtikçe yaygınlaşmaktadır. Bu çalışmanın amacı atık olarak değerlendirilen fındıkkabuğunun kompozit malzeme üretiminde kullanılabilirliğini araştırmaktır. Çalışmada, farklı boyutlara (maksimum: 50, 150, 250, 425 µm) ve ağırlıklara (5, 10, 15, 20 ) sahip fındıkkabuğu partikülleri dolgusu ile üretilen kompozit numunelere, ısıl kür işleminden sonra a/W= 0,3 olan başlangıç çentiği açılmıştır. Bu numunelerin mod I kırılma davranışları üç nokta eğme testi yardımı ile belirlenmiştir. Kritik Gerilme Şiddet Faktörü, Başlangıç Çentik Derinliği metodu yardımı ile hesaplanmıştır. Eğilme modülü ve eğilme gerilmeleri üç nokta eğme testi ile darbe dayanımı değerleri de Standart çentikler kullanılarak belirlenmiştir. Fındıkkabuğu /polimetilmetakrilat kompozitlerin bileşimi ve mikro yapısı Fouirer Transform Infrared Spektrofotometre ve Scanning Electron Microscope çalışmaları ile ortaya konulmuştur. Araştırmanın bulgularına göre, 0-50 µm boyutlarında fındıkkabuğu partikülleri ile üretilen kompozitlerin mekanik özellikleri daha büyük boyutlu kompozitlerden daha yüksektir.

Poly(ethylene glycol) diacrylate (PEGDA) has gained significant attention in biomedical research and 3D printing due to its biocompatibility, customizable mechanical properties, and ease of processing. Its acrylate functional groups facilitate UV-induced crosslinking and chemical modifications. This study produced and characterized PEGDA under 5 to 30 s curing times to assess its potential as a biomaterial. PEGDA was synthesized and confirmed using 1H-NMR and FTIR analysis, which showed that the material’s structure aligned with the existing literature. A 15% hydrogel solution was prepared using PEGDA, and curing times were adjusted using the DLP printer. FTIR analysis indicated the consumption of the terminal acrylate C=C groups, which is generally reflected by a decrease in the characteristic acrylate bands at approximately 1640 and 810 cm⁻¹ in the FTIR spectra. Compression tests revealed an increase in compressive strength from 14.08 kPa at 5 s to 53.48 kPa at 30 s. Additionally, after 5 s, the elastic modulus was measured at 42.23 kPa, and it increased to 160.44 kPa at 30 s, demonstrating an enhancement in the material’s stiffness. Numerical and theoretical natural frequencies increased, further supporting the role of curing time in material optimization. Finally, 30 s of curing exhibited more swelling and less degradation, confirming the role of curing time in controlling material behavior. These findings highlight PEGDA’s potential for biomaterial development in tissue engineering.