Dicarboxylic acid-epoxy vitrimers: influence of the off-stoichiometric acid content on cure reactions and thermo-mechanical properties

Vitrimers with 1 : 1 to 2 : 1 epoxy/acid ratio and TBD show increased stiffness and gradual transition from an exchangeable to non-exchangeable network.

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Determination of Mechanical Properties of Altered Dacite by Laboratory Methods

Minerals ◽

10.3390/min11080813 ◽

2021 ◽

Vol 11 (8) ◽

pp. 813

Author(s):

Veljko Rupar ◽

Vladimir Čebašek ◽

Vladimir Milisavljević ◽

Dejan Stevanović ◽

Nikola Živanović

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Rock Mass ◽

Uniaxial Compressive Strength ◽

Rock Material ◽

Strength Parameter ◽

Gradual Transition ◽

Strength Parameters ◽

Triaxial Compressive Strength ◽

Heterogeneous Rock

This paper presents a methodology for determining the uniaxial and triaxial compressive strength of heterogeneous material composed of dacite (D) and altered dacite (AD). A zone of gradual transition from altered dacite to dacite was observed in the rock mass. The mechanical properties of the rock material in that zone were determined by laboratory tests of composite samples that consisted of rock material discs. However, the functional dependence on the strength parameter alteration of the rock material (UCS, intact UCS of the rock material, and mi) with an increase in the participation of “weaker” rock material was determined based on the test results of uniaxial and triaxial compressive strength. The participation of altered dacite directly affects the mode and mechanism of failure during testing. Uniaxial compressive strength (σciUCS) and intact uniaxial compressive strength (σciTX) decrease exponentially with increased AD volumetric participation. The critical ratio at which the uniaxial compressive strength of the composite sample equals the strength of the uniform AD sample was at a percentage of 30% AD. Comparison of the obtained exponential equation with practical suggestions shows a good correspondence. The suggested methodology for determining heterogeneous rock mass strength parameters allows us to determine the influence of rock material heterogeneity on the values σciUCS, σciTX, and constant mi. Obtained σciTX and constant mi dependences define more reliable rock material strength parameter values, which can be used, along with rock mass classification systems, as a basis for assessing rock mass parameters. Therefore, it is possible to predict the strength parameters of the heterogeneous rock mass at the transition of hard (D) and weak rock (AD) based on all calculated strength parameters for different participation of AD.

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Approximate Functionally Graded Materials for Multi-Material Additive Manufacturing

Volume 1A: 38th Computers and Information in Engineering Conference ◽

10.1115/detc2018-86391 ◽

2018 ◽

Cited By ~ 2

Author(s):

Yuen-Shan Leung ◽

Huachao Mao ◽

Yong Chen

Keyword(s):

Mechanical Properties ◽

Additive Manufacturing ◽

Functionally Graded Materials ◽

Functionally Graded ◽

Gradual Transition ◽

Material Distribution ◽

Graded Materials ◽

Base Materials ◽

Multiple Materials ◽

Am Processes

Functionally graded materials (FGM) possess superior properties of multiple materials due to the continuous transitions of these materials. Recent progresses in multi-material additive manufacturing (AM) processes enable the creation of arbitrary material composition, which significantly enlarges the manufacturing capability of FGMs. At the same time, the fabrication capability also introduces new challenges for the design of FGMs. A critical issue is to create the continuous material distribution under the fabrication constraints of multi-material AM processes. Using voxels to approximate gradient material distribution could be one plausible way for additive manufacturing. However, current FGM design methods are non-additive-manufacturing-oriented and unpredictable. For instance, some designs require a vast number of materials to achieve continuous transitions; however, the material choices that are available in a multi-material AM machine are rather limited. Other designs control the volume fraction of two materials to achieve gradual transition; however, such transition cannot be functionally guaranteed. To address these issues, we present a design and fabrication framework for FGMs that can efficiently and effectively generate printable and predictable FGM structures. We adopt a data-driven approach to approximate the behavior of FGM using two base materials. A digital material library is constructed with different combinations of the base materials, and their mechanical properties are extracted by Finite Element Analysis (FEA). The mechanical properties are then used for the conversion process between the FGM and the dual material structure such that similar behavior is guaranteed. An error diffusion algorithm is further developed to minimize the approximation error. Simulation results on four test cases show that our approach is robust and accurate, and the framework can successfully design and fabricate such FGM structures.

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INFLUENCE OF ENVIRONMENTAL FACTORS ON PHYSICAL-MECHANICAL PROPERTIES OF POLYDIMETHYL ETHER OF NORBORENE -2;3-DICARBOXYLIC ACID

IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA ◽

10.6060/tcct.2017605.5511 ◽

2017 ◽

Vol 60 (5) ◽

pp. 68 ◽

Cited By ~ 1

Author(s):

Galina S. Bozhenkova ◽

Alexandra N. Tarakanovskaya ◽

Oksana D. Tarnovskaya ◽

Roman V. Ashirov

Keyword(s):

Mechanical Properties ◽

Glass Transition ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Hydrochloric Acid ◽

Environmental Factors ◽

Dicarboxylic Acid ◽

Uv Radiation ◽

Accelerated Aging ◽

The Impact

The article is devoted to the production of polymer by metathesis ring-opening polymerization under the influence of ruthenium initiator of type of Hoveyda-Grubbs II generation. The monomer used the mixture of dimethyl ether norbornene-2;3-dicarboxylic acid. The monomer was prepared by the Diels-Alder reaction of dicyclopentadiene and dimethyl maleate. The polymer was prepared in bulk of the monomer mixture. In this paper we have studied the physical and mechanical properties polydimethyl ether of norbornene-2;3-dicarboxylic acid; and assessed the impact of environmental factors on the change in properties of the polymer. As environmental factors; light; UV radiation; water; 0.1 M hydrochloric acid were applied; and accelerated aging conditions; which were held in a climate chamber. During performance we found that maintaining the polymer samples in the UV light chamber led to the slight increase in flexural modulus. In contrast; the polymer storage in water and in a hydrochloric acid solution for two months resulted in a slight decrease in the modulus of elasticity in bending index. These factors did not affect the change in the glass transition temperature of the polymer. Under the conditions of accelerated aging conducted for 1; 2 and 6 days after two cycles we observed the drop in modulus for bending of 8.5%; after 6 cycles of 13%. The glass transition temperature of polydimethyl ether of norbornene-2;3-dicarboxylic acid after 6 cycles decreased by only 3.4% in the climatic chamber. Studies have shown that the resulting polymer is resistant to water; hydrochloric acid; light and UV radiation; as well as it saves properties at a sufficient level for operation at conditions of accelerated aging. It should be noted that the tested polymer was prepared without additives; stabilizers and antioxidants. The proposed polymer can be used as a structural material for machine parts; including bulky.For citation:Bozhenkova G.S.; Tarakanovskaya A.N.; Tarnovskaya O.D.; Ashirov R.V. Influence of environmental factors on physical-mechanical properties of polydimethyl ether of norborene -2;3-dicarboxylic acid. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 5. P. 68-73

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CITRIC ACID AND POTASSIUM CONTENTS OF RUSSET BURBANK POTATO IN ALBERTA

Canadian Journal of Plant Science ◽

10.4141/cjps85-103 ◽

1985 ◽

Vol 65 (3) ◽

pp. 793-795 ◽

Cited By ~ 5

Author(s):

D. R. LYNCH ◽

M. S. KALDY

Keyword(s):

Citric Acid ◽

Chlorogenic Acid ◽

Acid Content ◽

Russet Burbank Potato ◽

Russet Burbank ◽

Potassium Content ◽

Potato Tubers ◽

Acid Ratio ◽

Southern Alberta ◽

Production Areas

Citric acid and potassium contents were determined for Russet Burbank tubers collected from the major production areas in Alberta. An increase in the ratio of citric to chlorogenic acid content is known to be associated with a decrease in the tendency for potato tubers to darken after cooking. Tuber citric acid and potassium contents were higher in southerly locations than in central locations. The trend for citric acid is the reverse of that for chlorogenic acid established in a previous study. Thus, potatoes grown at southern Alberta locations have a higher citric to chlorogenic acid ratio than those grown in central locations, suggesting that they would be less subject to after-cooking darkening.Key words: Darkening (after-cooking), citric acid, chlorogenic acid, potassium content, Russet Burbank, potato

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Curing behavior, thermal, and mechanical properties of epoxy resins cured with a novel liquid crystalline dicarboxylic acid curing agent

Polymer Engineering & Science ◽

10.1002/pen.23585 ◽

2013 ◽

Vol 54 (3) ◽

pp. 695-703 ◽

Cited By ~ 15

Author(s):

Le Hoang Sinh ◽

Nguyen Ngoc Trung ◽

Bui Thanh Son ◽

Seunghan Shin ◽

Dinh Tan Thanh ◽

...

Keyword(s):

Mechanical Properties ◽

Dicarboxylic Acid ◽

Epoxy Resins ◽

Liquid Crystalline ◽

Curing Agent ◽

Thermal And Mechanical Properties ◽

Curing Behavior

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The influence of composition of poly(n-isopropylacrylamide-co-itaconic acid) hydrogel on immobilized Candida rugosa lipase activity

Hemijska industrija ◽

10.2298/hemind0806339m ◽

2008 ◽

Vol 62 (6) ◽

pp. 339-344

Author(s):

Nikola Milasinovic ◽

Melina Kalagasidis-Krusic ◽

Zorica Knezevic-Jugovic ◽

Jovanka Filipovic

Keyword(s):

Mechanical Properties ◽

Itaconic Acid ◽

Lipase Activity ◽

Acid Content ◽

Immobilized Enzyme ◽

In Situ Polymerization ◽

Immobilized Lipase ◽

Candida Rugosa ◽

Candida Rugosa Lipase

The application of lipases as catalysts in chemical reactions has been deterred by the high cost of isolation and purification of enzymes, the instability of their structure when they are isolated from their natural environment, contamination of products with residual protein, their sensitivity to process conditions, etc. These problems could be overcome using immobilized lipases. Immobilization is achieved by fixing enzymes to or within solid supports and as a result a heterogeneous system is obtained. The present paper reports on the immobilization of Candida rugosa lipase in hydrogels based on N-isopropylacrylamide and itaconic acid. Immobilization of lipase is carried out by two different methods. In the first method, lipase is added to the reaction mixture before polymerization and crosslinking (in situ polymerization), while in the second method the synthetized hydrogels are immersed in lipase solution and left to rich the equilibrium swelling. The specific activities of the immobilized lipase were determined in both cases and compared. The amount of the immobilized lipase is higher if the immobilization is carried out by immersing hydrogel in lipase solution. It was observed that in both cases lipase activity increases with an increase of the itaconic acid content up to 10 wt% and thereafter decreases. From the measurements of shear storage moduli (G') it was concluded that the increase of the itaconic acid content decreases the mechanical properties of the hydrogels. SEM analysis confirmed the highly porous structure of hydrogels. It was found that greater pores were achieved when the enzyme was immobilized by in situ polymerization. When the enzyme was immobilized by in situ polymerization the itaconic acid content had not great effect on the mass of the immobilized enzyme, except for the 100/0 sample. On the contrary, for the samples where the enzyme was immobilized by swelling, the increase of the itaconic acid content increases the mass of the immobilized enzyme. Concerning the activity of the immobilized lipase, the swelling degree and mechanical properties of the investigated hydrogels, the best results were performed by the 95/5 hydrogel sample.

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Synthesis, properties and thermal behavior of poly(decylene-2,5-furanoate): a biobased polyester from 2,5-furan dicarboxylic acid

RSC Advances ◽

10.1039/c5ra13324f ◽

2015 ◽

Vol 5 (91) ◽

pp. 74592-74604 ◽

Cited By ~ 35

Author(s):

Vasilios Tsanaktsis ◽

Dimitrios N. Bikiaris ◽

Nathanael Guigo ◽

Stylianos Exarhopoulos ◽

Dimitrios G. Papageorgiou ◽

...

Keyword(s):

Mechanical Properties ◽

Melting Point ◽

Thermal Behavior ◽

Dicarboxylic Acid ◽

Low Density Polyethylene ◽

Low Density ◽

Linear Low Density Polyethylene ◽

Synthesis Properties ◽

Biobased Polyester

Poly(decylene-2,5-furandicarboxylate), a new bio-based polyester, was successfully synthesized from 2,5-furan dicarboxylic acid and 1,10-decanediol. It has mechanical properties and melting point similar to those of linear low density polyethylene.

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Microstructural Studies and Material Characterization of Alumina Nanoparticulate Reinforced Functionally Graded Al-12Si (wt.%) alloy, produced using Centrifuge Casting Technique

10.21203/rs.3.rs-767487/v1 ◽

2021 ◽

Author(s):

Chethan KS ◽

Kiran Aithal S ◽

Manjunath HN ◽

Ramesh Babu N ◽

Pavan KN

Keyword(s):

Mechanical Properties ◽

Research Work ◽

Primary Silicon ◽

Functionally Graded ◽

Gradual Transition ◽

Advanced Manufacturing ◽

Casting Technique ◽

Casting System ◽

Microstructural Studies

Abstract The current research work discusses the concept of reinforcing alumina nanoparticulate to Al-12Si (wt.%) alloy using a unique casting technique known as centrifuge casting system established in-house at our advanced manufacturing centre. The resulting cast solid cylindrical specimen will be functionally graded along the length of the specimen containing higher percentage of primary silicon and alumina nanoparticulate at the top region than the bottom region, with a gradual transition in between the two regions. The microstructure of the functionally graded Al-12Si (wt.%) alloy, reinforced with 0.5, 1 and 1.5wt.% of alumina nanoparticulate was analysed using “Scanning Electron Microscope (SEM)” and the elemental composition of the cast specimens were obtained using “Energy-dispersive X-ray analysis (EDX)”. The outcomes of the EDX analysis confirmed the presence of alumina nanoparticulate in the cast specimens. Further, the mechanical properties of the cast Al-12Si (wt.%) alloy, reinforced with alumina nanoparticulate were studied, and it was found that the specimen with the addition of alumina nanoparticulate showed enhanced mechanical properties when compared with the Al-12Si (wt.%) alloy, without alumina nanoparticulate addition, cast under identical conditions.

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Synthesis of copolyesters with bio-based lauric diacid: structure and physico-mechanical studies

RSC Advances ◽

10.1039/c7ra11771j ◽

2017 ◽

Vol 7 (87) ◽

pp. 55418-55426 ◽

Cited By ~ 2

Author(s):

Meiling Chen ◽

Nesren A. H. Saada ◽

Fei Liu ◽

Haining Na ◽

Jin Zhu

Keyword(s):

Mechanical Properties ◽

Dicarboxylic Acid ◽

Biodegradable Materials ◽

Long Chain ◽

Mechanical Studies

Copolyesters developed from bio-based long-chain dicarboxylic acid show promising mechanical properties that are helpful for their application as biodegradable materials.

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