Influence of cotton waste and flame-retardant additives on the mechanical, thermal, and flammability properties of phenolic novolac epoxy composites

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In this study, walnut shell (WSh), hazelnut shell (HSh), and mussel shell (MSh) waste as inexpensive reinforcements were recycled for the preparation of epoxy composite materials. Subsequent used inexpensive fillers are chars (WShC and HShC), which are the pyrolysis solid products of the natural WSh and HSh wastes. Three types of epoxy resins: bisphenol-A type (DGEBA), modified with polyurethane (MER with PU), and rubber modified (MER with rubber) epoxy resins were used as the matrix in MSh composites. Thermogravimetric analysis of the composites showed that the thermal strength of the epoxy matrix increased significantly with the MSh and chars. The best water sorption results were obtained with the MSh. The contact angle values of MSh composites prepared with DGEBA epoxy resin were quite high (111 -113.5 ) and their water retention values ranged from 0.2% to 0.32%. The composites that were produced using 50 wt% chars and the same epoxy resin showed better flammability stability. The full extinction times were determined as 63 and 58 s for WShC and HShC composites, respectively.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Water sorption, thermal, and fire resistance properties of natural shell‐based epoxy composites

Zamani

Kocaman

Işık

et al. 2022

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“…The EPN polymer chain contains many epoxide groups, which makes its molecule multifunctional. So when cured, it is highly cross‐linked due to its multifunctionality, leading to the high strength of the resultant materials 12,13 . The high chemical, solvent, and temperature resistance of EPNs are particularly useful for high‐performance applications and corrosion resistance.…”

Section: Introductionmentioning

confidence: 99%

“…A wide variety of curing agents can be used in the epoxy/clay nanocomposites, including amine‐type curing agents with different chemical structures, for example, triethylenetetramine, 17 diamino diphenylmethane, 18 diamino diphenyl sulfone, 19 and so forth. In the previous study, the author used cycloaliphatic amine as a hardener in the EPN resin 13 . Moreover, Kocaman and Ahmetli 20 studied the influence of the different hardeners (SAc—sebacic acid, MNA—methyl nadic anhydride, PhA—phthalic anhydride, MA—maleic anhydride, SA—succinic anhydride, cycloaliphatic polyamine Epamine PC 17, MXDA‐m‐xylenediamine, MI‐2‐methylimidazole and polyamide type Crayamid) on the curing process through FTIR spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

“…In the previous study, first untreated cotton waste (CtW), along with aluminum hydroxide (AH) and boric acid (BA) under different filler loadings first were used in EPN resin for the examination of the mechanical, thermal, and flammability properties of composites 13 . In studies that were different from our study in terms of both filler‐type and resin, cotton fabric wastes were used in thermoset unsaturated polyester resin, 28,29 also in epoxy, polyester orthophthalic, and polyurethane resins 30 .…”

Section: Introductionmentioning

confidence: 99%

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Cotton waste and nanoclay‐based phenolic novolac epoxy composites and evaluation of their properties

Soydal

2022

In this study, two types of biobased epoxy composites were prepared by using only alkali-treated cotton waste (CtW), or with the nanoclay (NC) in the form of hybrid reinforcement. Phenol novolac-type epoxy resin (EPN) was used as a matrix. Untreated (CtW) and alkali-treated (NaOH-CtW) particles were characterized by scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDX). The average size for NC was determined as 3838 nm.Composites were prepared at 10-50 wt% NaOH-CtW and 20 wt% NaOH-CtW/ (1-2-3-4-5) wt% NC ratios. The morphology of the composites was investigated using SEM. The composites' properties were determined by applying thermogravimetric analysis (TGA), and various tests (tensile, hardness, water sorption, and surface contact angle measurement). The tensile strength of pure EPN was 96.6 MPa, while it changed in the range of 74-98 and 81-106 MPa for NaOH-CtW and hybrid composites, respectively. All hybrid composites exhibited higher Young's modulus values (7.7-8.9 GPa). Thermal values of hybrid composites were found higher and their char percentages varied in the range of 28.9-30.3%. NaOH-CtW increased the water sorption of the epoxy matrix from 0.59% up to 6% by 50 wt%. In contrast, a decrease in water sorption of NC composites was observed.

Polystyrene waste‐modified epoxy/nanoclay and hybrid composite coatings

Özmeral

Kocaman

Soydal

et al. 2022

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In this study, phenolic novolac-type epoxy (EPN) resin was modified with 4 wt % thermoplastic polystyrene (PS) waste and was used as the polymer matrix for the first time. Two types of composites were prepared: (i) nanocomposites with 1-3 wt% nanoclay (NC) and (ii) hybrid composites. Pristine (NC) and tetramethylammonium chloride modified nanoclays (MNC) were used at a 2 wt% ratio in hybrid composites with 25-35 wt% red mud waste (RMW). The corrosion protection properties of the coatings were determined by immersion test in 5 wt% NaOH, HCl, and NaCl solutions. The water sorption of hybrid composites varied between 1%-3.6% and 1%-5.3%, while it was between 0.82% and 1.02% in EPN-PS/NC nanocomposites. The weight gain percentage values of hybrid composites in corrosive media for the base and salt solutions were determined much lower (0.59%-0.75% and 0.46%-0.59%, respectively) than water sorption. Surface morphologies of hybrid composites were examined by scanning electron microscopy before and after corrosion tests. MNC-30 wt% RMW hybrid composite was found more suitable due to high corrosion resistance in basic and salty environments, storage modulus, loss modulus, and glass transition temperature (T g ) values (90.6 C) as compared with NC-30 wt% RMW hybrid composite.