scholarly journals Furan Functionalized Polyesters and Polyurethanes for Thermally Reversible Reactive Hotmelt Adhesives

2021 ◽  
Author(s):  
Laxmisha M. Sridhar ◽  
Andrew T. Slark ◽  
James A. Wilson

New reactive hotmelt (RHM) adhesives based on thermally reversible Diels-Alder networks comprising multifunctional furan and maleimide prepolymers are described. The prepolymer mixture is easy to apply in the bulk from the melt and after application to the substrates, the adhesive undergoes polymerization at room temperature resulting in crosslinked bonds. Due to their thermoplastic nature and low melt viscosity at hot melt application temperatures, the adhesives provide processing properties similar to moisture cured polyurethanes (PUR). The technology is isocyanate-free and does not require moisture to initiate the crosslinking. Bonding and tensile properties of the RHM adhesive can be readily tuned by prepolymer design and provide cure rates similar to PUR adhesives. The Diels-Alder adhesives provide versatile adhesion to a variety of substrates and good creep resistance up to the retro temperature. The adhesives show good thermal stability during application and can be recycled multiple times by simple heating/cooling of the bonds providing similar performance. Several furan and maleimide prepolymers were scaled up to multi-Kg quantities to demonstrate the potential for industrial scalability. The results demonstrate that furan-maleimide reversible chemistry can be used for RHM application as a more sustainable alternative to conventional moisture curing PURs which tend to contain harmful residual isocyanate monomers.

1992 ◽  
Vol 4 (1) ◽  
pp. 19-33 ◽  
Author(s):  
Hasmukh S. Patel ◽  
Harshad D. Patel

Polyimides were prepared by Diels-Alder (DA) reaction of furfuralacetone (FAC) resin [poly(4-furanyl-butan-2-one)] with various bismaleimides. The DA reaction was carried out in tetrahydrofuran (THF) as solvent as well as in bulk, followed by aromatization of the tetrahydrophthalimide intermediates in the presence of acetic anhydride. All the polyimides were characterized by elemental analysis, IR spectral studies and thermogravimetry. The results show that polyimides based on FAC resin exhibit good thermal stability. Preliminary tests for glass reinforcement of the polyimides indicate that laminates with good mechanical strength can be prepared.


2019 ◽  
Vol 50 (6) ◽  
pp. 921-938
Author(s):  
Zongqian Wang ◽  
Dengfeng Wang ◽  
Zun Zhu ◽  
Wei Li ◽  
Yanxia Xie

In this paper, the compound hot-melt adhesives were prepared by blending alkyl sulfonate polymer antistatic agent with modified rosin hot-melt adhesive and used for the preparation of polyethylene film/polypropylene-coated non-woven fabrics. The effects of the amount of antistatic agent on the melt viscosity, softening point, and thermal stability of the compounded hot-melt adhesives were studied. Then, the antistatic properties and its washing fastness of the coated non-woven fabrics were tested and analyzed. The results showed that the softening point and the melt viscosity of the hot-melt adhesives decreased after compounding, and the thermal stability of the compound hot-melt adhesives decreased in the high temperature range, which was not affected before 200℃. The surface inductive voltage, half-life, and specific resistance of the coated non-woven fabrics prepared from the compound adhesives decreased gradually with the increase of the amount of the antistatic agent, indicating that the antistatic property of the prepared fabrics was gradually improved. In addition, the fabrics still exhibited antistatic properties after soaping for several times. The influence of compound adhesive on the wettability of fabric surface was consistent with that of antistatic property. Finally, the mechanism of the hot-melt adhesive and antistatic agent compounding technology to improve the antistatic performance of the coated non-woven fabrics was elaborated, and the reason for its excellent soaping durability was also explained.


2012 ◽  
Vol 531-532 ◽  
pp. 8-12
Author(s):  
M.A. Sai Balaji ◽  
K. Kalaichelvan

Organic fibres (Kevlar/ Arbocel / Acrylic) have good thermal stability, higher surface area and bulk density. The optimization of organic fibres percentage for thermal behaviour is considered using TGA. The temperature raise during brake application will be between 150-4000 C and this temperature zone is very critical to determine the fade characteristics during friction testing. Hence, three different friction composites are developed with the same formulation varying only the Kevlar, Arbocel and Acrylic fibres which are compensated by the inert filler namely the barites and are designated as NA01, NA02 and NA03 respectively. After the fabrication, the TGA test reveals that the composite NA03 has minimum weight loss. The friction coefficient test rig is then used to test the friction material as per SAE J661a standards. The results prove that the brake pad with minimum weight loss during TGA has higher friction stability. Thus, we can correlate the thermal stability with the stability of friction.


Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 31
Author(s):  
Hongxin Liao ◽  
Taekyung Lee ◽  
Jiangfeng Song ◽  
Jonghyun Kim ◽  
Fusheng Pan

The microstructures and mechanical properties of the Mg88.5Zn5Y6.5-XREX (RE = Yb and Ce, X = 0, 1.5, 3.0, and 4.5) (wt.%) alloys were investigated in the present study. Mg88.5Zn5Y6.5 is composed of three phases, namely, α-Mg, long-period stacking ordered (LPSO) phases, and intermetallic compounds. The content of the LPSO phases decreased with the addition of Ce and Yb, and no LPSO phases were detected in Mg88.5Zn5Y2.0Yb4.5. The alloys containing the LPSO phases possessed a stratified microstructure and exhibited excellent mechanical properties. Mg88.5Zn5Y5.0Ce1.5 exhibited the highest creep resistance and mechanical strength at both room temperature and 200 °C, owing to its suitable microstructure and high thermal stability. The yield strength of Mg88.5Zn5Y5.0Ce1.5 at room temperature was 358 MPa. The ultimate tensile strength of Mg88.5Zn5Y5.0Ce1.5 at room temperature and 200 °C was 453 MPa and 360 MPa, respectively.


2013 ◽  
Vol 734-737 ◽  
pp. 2191-2194
Author(s):  
Li Li Wu ◽  
Yuan Lian ◽  
Dan Liu ◽  
Hua Zheng ◽  
Dian Wu Huang

In this study, flame retardant microcapsules were synthesized using magnesium hydroxide as core materials, melamine resin as the shell material. The structure, diameters and thermal properties of prepared microcapsules were investigated by using FTIR, ELS, DSC and TGA. The effects of core/shell ratio on the properties of microcapsules were studied.Flame retardant materials of low-density polyethylene/magnesium hydroxide microcapsules were prepared.The tensile strength and elongation at break tests were performed to determine its mechanical property.Inflammability of the materials was also studied.The results showed the prepared magnesium hydroxide microcapsule shows good thermal stability and it has free compatibility with the polymer.The composites of HDPE/MH microcapsules have good performance.


2013 ◽  
Vol 829 ◽  
pp. 62-66 ◽  
Author(s):  
Alireza Fallahi ◽  
Hossein Hosseini-Toudeshky ◽  
Seyed Mahmoud Ghalehbandi

It is the objective of this study to investigate the effect of ECAP processing and heat treatment on the mechanical properties of the UFG 7075 alloy. Also the effect of post ECAP heat treatment is investigated. The alloy is processed by ECAP after annealing as well as solution treatment to produce an UFG structure. Furthermore mechanical properties and their variations during annealing and aging are investigated. The hardness of the pre-ECAP annealed and the pre-ECAP solutionised 7075 aluminum alloy has increased significantly compared with that of the CG sample. Also hardness of ECAPed specimen has not experienced significant changes in post-ECAP heat treatment and indicated that the alloy had approximately good thermal stability.


RSC Advances ◽  
2016 ◽  
Vol 6 (90) ◽  
pp. 87013-87020 ◽  
Author(s):  
Kaiju Luo ◽  
Yan Wang ◽  
Junrong Yu ◽  
Jing Zhu ◽  
Zuming Hu

Aromatic furanic polyamides with relatively high molecular weight were synthesized, and good thermal stability and mechanical properties were demonstrated.


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