Polymers

Research

15 pages, 8205 KiB

Open AccessArticle

Flexural Properties of Heat-Polymerized PMMA Denture Base Resins Reinforced with Fibers with Different Characteristics

by Kaan Yerliyurt, Taha Buğra Taşdelen, Özlem Eğri and Sinan Eğri

Polymers 2023, 15(15), 3211; https://doi.org/10.3390/polym15153211 - 28 Jul 2023

Cited by 3 | Viewed by 1859

Polymethylmethacrylate (PMMA) has been the most-widely used denture base material in prosthetic dentistry for the last 80 years. It is still one of the best alternatives when new methods are inapplicable. Due to the lack of some physical inadequacies occurring during cyclic use [...] Read more.

Polymethylmethacrylate (PMMA) has been the most-widely used denture base material in prosthetic dentistry for the last 80 years. It is still one of the best alternatives when new methods are inapplicable. Due to the lack of some physical inadequacies occurring during cyclic use and accidental situations, various reinforcement strategies such as using nanoparticles, wires, fibers, and meshes have been investigated and reported. In this study, it was aimed to conduct a comparative investigation of the effect of fiber additives with different characteristics on the flexural properties of heat-cured PMMA denture base resins. Glass fibers (GFs), polypropylene fibers (PPFs), and carbon fibers (CFs) having 3, 6, and 12 mm lengths and 0.25, 0.50, and 1.0% concentrations (v/v) were used for the reinforcement of PMMA denture base resins. The flexural properties (flexural strength, flexural modulus, and maximum deformation) were determined using a three-point bending test, and three-way ANOVA analyses with Bonferroni corrections were performed on the test results. The morphologies of the fracture surfaces were analyzed using scanning electron microscopy. All three fibers exhibited reinforcement in the flexural strength (p < 0.001) and flexural modulus (p < 0.001) regardless of their length and concentration. The group with 1.0% 12 mm CF-reinforced PMMA exhibited the greatest flexural strength (94.8 ± 8.8 MPa), and that with 1.0% 3 mm GFs displayed the lowest flexural strength (66.9 ± 10.4 MPa) among the fiber-reinforced groups. The greatest value of the flexural modulus was displayed by the 1.0% 3 mm CF-reinforced resin (3288.3 ± 402.1 MPa). Although the CF-reinforced groups exhibited better flexural properties, CFs are not favorable for use as reinforcement in practice due to the dark gray discoloration of the denture base resin. It was concluded that PPF is a promising material for the reinforcement of heat-cured PMMA denture base resins. Full article

(This article belongs to the Special Issue Additive Manufacturing of Fiber-Reinforced Polymer Composites)

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13 pages, 3949 KiB

Open AccessArticle

Significant Influence of Bound Rubber Thickness on the Rubber Reinforcement Effect

by Jian Chen, Maoyuan Hu, Yuming Li, Rui Li and Long Qing

Polymers 2023, 15(9), 2051; https://doi.org/10.3390/polym15092051 - 26 Apr 2023

Cited by 1 | Viewed by 1436

Abstract

In this work, the contribution of different types of carbon blacks (N115, N330, N550, N660) and their primary and secondary thermally cracked recovered carbon blacks to the mechanical properties of NR composites was evaluated. The thermally cracked recovered carbon blacks were prepared by [...] Read more.

In this work, the contribution of different types of carbon blacks (N115, N330, N550, N660) and their primary and secondary thermally cracked recovered carbon blacks to the mechanical properties of NR composites was evaluated. The thermally cracked recovered carbon blacks were prepared by cracking the rubber composites at 500 °C and de-hybridizing them at 900 °C. The characterization of the thermally cracked recovered carbon blacks by scanning electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy showed that carbon blacks after primary and secondary thermal cracking recovery were more prone to aggregation and exhibited a higher degree of carbon defects. The number and type of functional groups on the surface of these carbon blacks were significantly reduced. For NR composites with pristine samples added, the mechanical properties and the bound rubber content tests showed that the mechanical properties of the NR composites became weaker with the increase in carbon black particle size. The bound rubber content also decreased with increased carbon black particle size. The mechanical properties of the NR composites reinforced with carbon black recovered by primary and secondary thermal cracking would therefore decrease. The results of AFM and DSC tests further confirmed the decreasing trend of bound rubber. The present work demonstrates the effect of bound rubber content variation on the mechanical properties of rubber, demonstrates the morphology of bound rubber more visually, and provides new insights into the reinforcement theory of CB. Full article

(This article belongs to the Special Issue Additive Manufacturing of Fiber-Reinforced Polymer Composites)

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15 pages, 3807 KiB

Open AccessArticle

Experimental Analysis of Fiber Reinforcement Rings’ Effect on Tensile and Flexural Properties of Onyx™–Kevlar^® Composites Manufactured by Continuous Fiber Reinforcement

by Benjamín Alberto Moreno-Núñez, César Gustavo Abarca-Vidal, Cecilia D. Treviño-Quintanilla, Ulises Sánchez-Santana, Enrique Cuan-Urquizo and Esmeralda Uribe-Lam

Polymers 2023, 15(5), 1252; https://doi.org/10.3390/polym15051252 - 1 Mar 2023

Cited by 9 | Viewed by 2658

Abstract

Additive manufacturing of composite materials is progressing in the world of 3D printing technologies; composite materials allow the combination of the physical and mechanical properties of two or more constituents to create a new material that meets the required properties of several applications. [...] Read more.

Additive manufacturing of composite materials is progressing in the world of 3D printing technologies; composite materials allow the combination of the physical and mechanical properties of two or more constituents to create a new material that meets the required properties of several applications. In this research, the impact of adding Kevlar^® reinforcement rings on the tensile and flexural properties of the Onyx™ (nylon with carbon fibers) matrix was analyzed. Parameters such as infill type, infill density and fiber volume percentage were controlled to determine the mechanical response in tensile and flexural tests of the additive manufactured composites. The tested composites showed an increment of four times the tensile modulus and 1.4 times the flexural modulus of pure Onyx™ matrix when compared with that of the Onyx™–Kevlar^®. The experimental measurements demonstrated that Kevlar^® reinforcement rings can increase the tensile and flexural modulus of Onyx™–Kevlar^® composites using low fiber volume percentages (lower than 19% in both samples) and 50% of rectangular infill density. However, the appearance of some defects, such as delamination, was observed and should be further analyzed to obtain products that are errorless and can be reliable for real functions as in automotive or aeronautical industries. Full article

(This article belongs to the Special Issue Additive Manufacturing of Fiber-Reinforced Polymer Composites)

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12 pages, 4121 KiB

Open AccessArticle

Highly Strong Interface Adhesion of Polyester Fiber Rubber Composite via Fiber Surface Modification by Meta-Cresol/Formaldehyde Latex Dipping Emulsion

by Xiangze Meng, Le Kang, Xin Guo, Xiaohao Tang, Li Liu and Mei Shen

Polymers 2023, 15(4), 1009; https://doi.org/10.3390/polym15041009 - 17 Feb 2023

Cited by 4 | Viewed by 2528

Abstract

As a skeleton material, polyester (PET) fiber can significantly improve the strength and durability of rubber composites, but the interfacial adhesion between polyester fiber and rubber is poor due to the chemical inertia of PET fiber surface. Resorcinol-formaldehyde-latex (RFL) impregnating solution is usually [...] Read more.

As a skeleton material, polyester (PET) fiber can significantly improve the strength and durability of rubber composites, but the interfacial adhesion between polyester fiber and rubber is poor due to the chemical inertia of PET fiber surface. Resorcinol-formaldehyde-latex (RFL) impregnating solution is usually used to treat PET fibers, but RFL contains toxic components such as resorcinol, which is harmful to the human body. A simple and less toxic resin-impregnating system cresol-formaldehyde-latex (CFL) was obtained by alternating resorcinol with low-toxicity cresol and m-cresol formaldehyde resin was synthesized from m-cresol and formaldehyde. CFL (m-cresol formaldehyde resin latex) systems with different C/F mole ratios and CF resin/latex ratios were adopted to modify the surface of PET fibers. The strip peeling adhesive and the H pull-out test results indicated that the PET fiber/rubber adhesion strength increased with the increase in the formaldehyde dosage and the CF resin content, and the peeling force value and the H-pull-out force of treated PET/rubber composites reached 7.3 N/piece and 56.8 N, respectively. The optimal choice of CFL adhesive system was obtained, when the C/F mole ratio was 1/2 and the CF resin/latex weight ratio was 0.23. This environment-friendly CFL dipping emulsion can be used as a new surface modification strategy as it can remarkably enhance the interfacial adhesion of PET/rubber composites. Full article

(This article belongs to the Special Issue Additive Manufacturing of Fiber-Reinforced Polymer Composites)

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13 pages, 2734 KiB

Open AccessArticle

Influence of Polymer Matrices on the Tensile and Impact Properties of Long Fiber-Reinforced Thermoplastic Composites

by Lijuan Jiang, Yinzhi Zhou, Fengnian Jin and Zhenhua Hou

Polymers 2023, 15(2), 408; https://doi.org/10.3390/polym15020408 - 12 Jan 2023

Cited by 2 | Viewed by 1763

Abstract

To investigate the influence of polymer matrices on the tensile and impact properties of long fiber-reinforced thermoplastic (LFT) composites, composites of long basalt fiber-reinforced thermoplastic were developed in this work. Two types of polyethylene, namely 8008 and 100S, and two types of polyethylene, [...] Read more.

To investigate the influence of polymer matrices on the tensile and impact properties of long fiber-reinforced thermoplastic (LFT) composites, composites of long basalt fiber-reinforced thermoplastic were developed in this work. Two types of polyethylene, namely 8008 and 100S, and two types of polyethylene, namely C4220 and K8303, were chosen as the matrices. The fiber volume fractions were set as 2.8%, 5.9%, 8.1%, and 10.6%. The melt flow index (MFI), crystallinity, tensile properties, impact strength, and fracture morphology of the neat polymers and the corresponding composites were tested. The composites of 8008 showed the highest tensile strength since neat 8008 showed a much higher MFI value and crystallinity. The composites of 8008 and K8303 showed a much higher tensile modulus since the neat thermoplastic showed a higher tensile modulus than the other two composites. The polymer toughness was the factor that determined whether the polymer could be toughened by fibers. Moreover, the interfacial shear strength was calculated and compared with the matrix shear strength, based on which fracture modes of the LFT were predicted. Effective methods were proposed for further improvement of the mechanical properties. The results of this paper were essential for attaining the anticipated properties when designing LFT composites. Full article

(This article belongs to the Special Issue Additive Manufacturing of Fiber-Reinforced Polymer Composites)

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15 pages, 3880 KiB

Open AccessArticle

A Comparative Evaluation of the Effects of Manufacturing Parameters on Mechanical Properties of Additively Manufactured PA and CF-Reinforced PA Materials

by Mumin Tutar

Polymers 2023, 15(1), 38; https://doi.org/10.3390/polym15010038 - 22 Dec 2022

Cited by 11 | Viewed by 1488

Abstract

Nowadays, 3D printers, which have a wide range of applications, continue to become widespread and are more and more common. As a result, in addition to the visuality of the parts produced with this method, their mechanical properties have gained importance depending on [...] Read more.

Nowadays, 3D printers, which have a wide range of applications, continue to become widespread and are more and more common. As a result, in addition to the visuality of the parts produced with this method, their mechanical properties have gained importance depending on where they are used. In addition to the many conveniences, it provides during the design and production phases according to traditional methods the features of the printing parameters used, especially the printing direction and angle, which vary depending on the direction. For this reason, it is necessary to determine how the mechanical properties change depending on these parameters. In this study, compression, tensile, and bending tests were carried out with samples produced by the FDM method using polyamide (PA) and carbon fiber reinforced PA (PA-CF) filaments. The effects of fiber reinforcement, raster angle, and frame on the mechanical properties were evaluated. The porosity of manufactured parts was also discussed. Full article

(This article belongs to the Special Issue Additive Manufacturing of Fiber-Reinforced Polymer Composites)

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21 pages, 7324 KiB

Open AccessArticle

Investigations on the Fatigue Behaviour of 3D-Printed Continuous Carbon Fibre-Reinforced Polymer Tension Straps

by Tadej Vidrih, Peter Winiger, Zafiris Triantafyllidis, Valentin Ott and Giovanni P. Terrasi

Polymers 2022, 14(20), 4258; https://doi.org/10.3390/polym14204258 - 11 Oct 2022

Cited by 1 | Viewed by 1555

Abstract

The focus of this research is an investigation on the fatigue behaviour of unidirectional 3D-printed continuous carbon fibre-reinforced polymer (CFRP) tension straps with a polyamide matrix (PA12). Conventionally produced tension straps are becoming established components in the mechanical as well as the civil [...] Read more.

The focus of this research is an investigation on the fatigue behaviour of unidirectional 3D-printed continuous carbon fibre-reinforced polymer (CFRP) tension straps with a polyamide matrix (PA12). Conventionally produced tension straps are becoming established components in the mechanical as well as the civil engineering sector, e.g., as rigging systems for sailing boats and cranes and—recently introduced—as network arch bridge hangers. All these structures are subjected to high fatigue loads, and although it is commonly reported that carbon fibre-reinforced polymers show excellent fatigue resistance, there is limited understanding of the behaviour of CFRP loop elements under such loads, especially in combination with fretting at the attachment points. Research on this topic was performed at Empa in the past decade on thermoset CFRP straps, but never before with 3D-printed continuous CFRP straps with a thermoplastic matrix. This paper examines an additive manufacturing and post-consolidation method for producing the straps and presents initial results on their fatigue performance, which show that the fatigue endurance limit of the investigated 3D-printed and post-consolidated CFRP strap design is acceptable, when compared to steel tendons. However, it is still 20% lower than conventionally produced CFRP straps using out-of-autoclave unidirectional carbon fibre prepregs. The reasons for these findings and potential future improvements are discussed. Full article

(This article belongs to the Special Issue Additive Manufacturing of Fiber-Reinforced Polymer Composites)

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21 pages, 5732 KiB

Open AccessArticle

Production and Assessment of Poly(Lactic Acid) Matrix Composites Reinforced with Regenerated Cellulose Fibres for Fused Deposition Modelling

by Christian Gauss, Kim L. Pickering, Joshua Tshuma and John McDonald-Wharry

Polymers 2022, 14(19), 3991; https://doi.org/10.3390/polym14193991 - 23 Sep 2022

Cited by 9 | Viewed by 1644

Abstract

Additive manufacturing can be a valuable tool to process polymeric composites reinforced with bio-based fibres, extending their use and opening new opportunities for more environmentally friendly materials. In this work, poly(lactic acid) (PLA) composites reinforced with regenerated cellulose fibres (lyocell) were processed into [...] Read more.

Additive manufacturing can be a valuable tool to process polymeric composites reinforced with bio-based fibres, extending their use and opening new opportunities for more environmentally friendly materials. In this work, poly(lactic acid) (PLA) composites reinforced with regenerated cellulose fibres (lyocell) were processed into novel filaments and used for 3D printing. The Young’s modulus of the filaments increased with the addition of fibres, but substantial porosity was observed in formulations with 20 and 30 wt% of fibre content. Nonetheless, the composites were easily printed, and the formulation with 10 wt% of fibres presented the best tensile properties of 3D printed samples with average tensile strength, Young’s modulus, and strain at break of 64.2 MPa, 4.56 GPa, and 4.93%, respectively. It has been shown in this study that the printing process contributes to fibre alignment with small variations depending on the printing speed. Printed composite samples also had superior thermo-mechanical stability with a storage modulus up to 72 times higher than for neat PLA at 80 °C after the composite samples were heat-treated. In general, this work supports the potential use of regenerated cellulose fibres to reinforce PLA for 3D printing applications. Full article

(This article belongs to the Special Issue Additive Manufacturing of Fiber-Reinforced Polymer Composites)

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