scholarly journals Study on Optimization of Damping Performance and Damping Temperature Range of Silicone Rubber by Polyborosiloxane Gel

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1196 ◽  
Author(s):  
Jiang Zhao ◽  
Nan Jiang ◽  
Dongsheng Zhang ◽  
Bobing He ◽  
Xian Chen
Keyword(s):  
Silicone Rubber ◽  
Intermolecular Forces ◽  
Mechanical Analysis ◽  
Covalent Bonding ◽  
Cross Linking ◽  
Damping Properties ◽  
Transfer Energy ◽  
Covalent Bonds ◽  
Combined Action ◽  
Rheological Test

Polyborosiloxane gel (PBS-gel) with shear hardening properties was prepared by cross-linking boric acid and hydroxyl-terminated polydimethylsiloxane through B–O–Si dynamic covalent bonding. The prepared PBS gel was mixed with methyl vinyl silicone rubber (MVQ), and a benzoyl peroxide (BPO) cross-linking agent was added to vulcanize the silicone rubber. At the same time, the gel molecules were co-vulcanizing with MVQ to produce molecular cross-linking. The effects of PBS-gel on the damping properties of silicone rubber were analyzed by dynamic rheological test, Fourier transform infrared spectroscopy and dynamic mechanical analysis. The results demonstrated that the damping performance of MVQ/PBS rubber is greatly improved and the rubber has a tanδ > 0.3 in the range of −25~125 °C. The shear-hardening gel is uniformly dispersed in the system, due to the combined action of covalent bonds and intermolecular forces, which act as an active molecular chain that can efficiently dissipate and transfer energy inside the silicone rubber.

scholarly journals Natural Tannins as New Cross-Linking Materials for Soy-Based Adhesives

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 595
Author(s):  
Saman Ghahri ◽  
Xinyi Chen ◽  
Antonio Pizzi ◽  
Reza Hajihassani ◽  
Antonios N. Papadopoulos
Keyword(s):  
Chemical Bond ◽  
Urea Formaldehyde ◽  
Bond Formation ◽  
Research Work ◽  
Formaldehyde Emission ◽  
Mechanical Analysis ◽  
Cross Linking ◽  
Covalent Bonds ◽  
Chemical Bond Formation ◽  
Tof Ms

Human health problems and formaldehyde emission from wood-based composites are some of the major drawbacks of the traditional synthetic adhesives such as urea formaldehyde resins. There have been many attempts to decrease formaldehyde emission and replace urea formaldehyde resins with bio-based adhesives for wood-based composites. Because of some weakness in soy-based adhesive, chemicals have been used as modifiers. Modified soy-based adhesives without any formaldehyde have been successfully used to prepare wood panels. To achieve this, different synthetic cross-linking chemicals such as phenol formaldehyde resins and polyamidoamine-epichlorohydrin were used. However, in reality, what we need are totally green adhesives that use natural materials. In our previous research work, the use of tannins in combination with soy-based adhesives to make wood composites was investigated. Thus, in this research work, the feasibility of using three types of natural tannins (quebracho, mimosa and chestnut tannins) as cross-linking materials for soy adhesive was studied. The chemical bond formation and adhesion behaviors of tannin-modified soy adhesives were also investigated by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-ToF-MS) and thermo-mechanical analysis (TMA). The results showed that at ambient temperature, both ionic and covalent bonds formed between tannin constituents and amino acids; however, at higher temperature, covalent bonds are largely predominate. Based on the results obtained from the thermo-mechanical analysis, the modulus of elasticity (MOE) of soy adhesive is increased by adding tannins to its formulation. In addition, the chemical bond formation was proved by MALDI-ToF-MS.

scholarly journals Enzymatic and Chemical Cross-Linking of Bacterial Cellulose/Fish Collagen Composites—A Comparative Study

2021 ◽  
Vol 22 (7) ◽  
pp. 3346
Author(s):  
Agata Sommer ◽  
Paulina Dederko-Kantowicz ◽  
Hanna Staroszczyk ◽  
Sławomir Sommer ◽  
Marek Michalec
Keyword(s):  
Thermal Stability ◽  
Bacterial Cellulose ◽  
Secondary Alcohol ◽  
Water Vapor Permeability ◽  
Polymer Chains ◽  
Cross Linking ◽  
Vapor Permeability ◽  
Covalent Bonds ◽  
Fish Collagen ◽  
Chemical Cross Linking

This article compares the properties of bacterial cellulose/fish collagen composites (BC/Col) after enzymatic and chemical cross-linking. In our methodology, two transglutaminases are used for enzymatic cross-linking—one recommended for the meat and the other proposed for the fish industry—and pre-oxidated BC (oxBC) is used for chemical cross-linking. The structure of the obtained composites is characterized by scanning electron microscopy, thermogravimetric analysis, X-ray diffraction, and Fourier transform infrared spectroscopy, and their functional properties by mechanical and water barrier tests. While polymer chains in uncross-linked BC/Col are intertwined by H-bonds, new covalent bonds in enzymatically cross-linked ones are formed—resulting in increased thermal stability and crystallinity of the material. The C2–C3 bonds cleavage in D-glucose units, due to BC oxidation, cause secondary alcohol groups to vanish in favor of the carbonyl groups’ formation, thus reducing the number of H-bonded OHs. Thermal stability and crystallinity of oxBC/Col remain lower than those of BC/Col. The BC/Col formation did not affect tensile strength and water vapor permeability of BC, but enzymatic cross-linking with TGGS improved them significantly.

A strengthening approach for damping property and shape memory property of acrylic rubber/polylactide blends

2018 ◽  
Vol 51 (7-8) ◽  
pp. 626-643
Author(s):  
Chengliang Li ◽  
Xingxing Ji ◽  
Yang Lyu ◽  
Xinyan Shi
Keyword(s):  
Shape Memory ◽  
Loss Factor ◽  
Phenol Formaldehyde ◽  
Mechanical Analysis ◽  
Damping Properties ◽  
Shape Memory Property ◽  
Memory Property ◽  
Damping Material ◽  
Shape Memory Properties ◽  
Shape Memory Effects

In this work, a damping material was successfully prepared by blending acrylic rubber (ACM) and polylactide (PLA) with sulfur and soap salt as the curing agents. A phenol-formaldehyde (PF) resin was used as a modifier. The effects of PF on the mechanical properties, damping properties, compatibility and shape memory properties of the blends were studied. The compatibility and damping properties were characterized by dynamic mechanical analysis, Fourier transform infrared spectroscope and microstructure analysis. The shape memory properties were examined by thermal mechanical analyser. The results revealed that the tensile strength of the blends was decreased and the toughness was increased with the increase of PF loadings. The introduction of PF improved the compatibility between PLA and ACM, which was deduced from the fact that the glass transition temperature of ACM was increased and the two loss factor peaks became closer. It was also found that the loss factor peak became higher and the effective damping temperature range became wider due to the formation of hydrogen bonding, implying that the damping properties of ACM/PLA blends were significantly improved. The ACM/PLA blends exhibited good dual-shape memory effect and its shape recovery ratio was increased by introduction of PF and raising the trigger temperature. The blends also exhibited good triple-shape memory property, which was dramatically improved by the introduction of PF. The mechanisms for the enhanced shape memory effects were then analysed.

scholarly journals Thermal analysis of halogenated rubber cured with a new cross-linking system

2019 ◽  
Vol 138 (6) ◽  
pp. 4395-4405 ◽  
Author(s):  
Anna Dziemidkiewicz ◽  
Magdalena Maciejewska ◽  
Martyna Pingot
Keyword(s):  
Mechanical Properties ◽  
Cross Linking ◽  
Curing Agent ◽  
Metal Acetylacetonates ◽  
Damping Properties ◽  
Rubber Blends ◽  
Rubber Compounds ◽  
Curing Agents ◽  
Brominated Butyl Rubber ◽  
Thermal Stability Of

Abstract The aim of this work was to examine the influence of new curing agents proposed for brominated butyl rubber (BIIR) on the cross-linking process of rubber compounds and the thermal behavior of the vulcanizates. Rubber blends that were filled with carbon black and contained acetylacetonates of different transition metals in the presence of triethanolamine (TEOA) as new cross-linking agents were prepared. The performed studies showed that metal acetylacetonates (Me(acac)) are effective cross-linking agents for BIIR, which was confirmed by high values of the torque increment (∆M) and significant cross-linking degree of the vulcanizates (α(T)). The most active curing agent seems to be iron acetylacetonate (Fe(acac)). Its application results in a shorter optimal vulcanization time, lower onset vulcanization temperature and similar vulcanization enthalpy compared to the BIIR cured with a sulfur curing system. The BIIR vulcanizates cured with Me(acac) reveal good mechanical properties with tensile strengths in the range of 9–14 MPa and better damping properties comparing to the sulfur-cured rubber. The proposed curing agents do not significantly affect the thermal stability of the BIIR vulcanizates.

scholarly journals OCCUPATIONAL AND PUBLIC HEALTH. THE WRINKLE RECOVERY ANGLE (WRA) STUDY OF FABRIC THAT NANO-SILVER TREATED

2020 ◽  
Vol 36 (1) ◽  
pp. 3-11
Author(s):  
A. M. Pirzada ◽  
S. Vambol ◽  
Z. Khatri ◽  
A. Aziz ◽  
N. A. Samoon ◽  
...  
Keyword(s):  
Standard Method ◽  
Sleep Disturbances ◽  
Flexural Rigidity ◽  
Test Method ◽  
Cross Linking ◽  
Health State ◽  
Covalent Bonds ◽  
Whiteness Index ◽  
Nano Silver ◽  
Recovery Angle

The constant use of wrinkle-resistant cellulose fabrics in professional and everyday life can negatively affect the health state. This is because formaldehyde vapours, which contribute to allergies, persistent coughing, and irritation of the eyes, nose, and throat, sleep disturbances, headaches, etc., pose a greater danger. In this study an attempt was made to achieve fabric stabilization from wrinkle resistant by formation ionic bonds of as replacement covalent bonds. And this is the main study purpose. Industrially Desized and Bleached 100 % pure cotton fabric with the weight of 110 g/m2, and the chemicals were used. Preparation of cationic glycerine, carboxymethylation of bleached fabric and application of antimicrobial finishes on the ionic cross-linked fabric was provided. Measurements were taken to determine of wrinkle recovery angle (WRA), of absorbency, of whiteness index, of flexural rigidity, of abrasion, of tensile strength. Wrinkle recovery angle was measured by standard method of AATCC 66 (option 2). AATCC Test Method 79-2000 was used to test the absorbency of fabric. The CIE whiteness index was determined using an Xrite Colour Eye 7000A spectrophotometer. Flexural Rigidity was measured through a testing cantilever method ASTM D-1388. Fabric abrasion was checked according to standard method for abrasion resistance of textile fabric ASTM 4966 on Martindale Abrasion Device M235. Mechanical strength of the fabric was measured under the standard method of ASTM D-5034. With the ionic cross-linking, the dry WRA was achieved an optimum of 118º and wet WRA up to 128º with increased fabric strength and whiteness. In addition to ionic cross-linking fabric was treated with Nano silver. Based on the results it was concluded that the fabric can be optimized first with ionic cross-link method and then it can be treated with the antimicrobial making the fabric cleaner and hygienic. This fabric treatment provides the necessary characteristics and is safe for the health of the people who use it.

scholarly journals THE INFLUENCE OF SEVERAL TYPES OF RESINS ON THE DYNAMIC MECHANICAL PROPERTIES OF POLYMER MIXTURE BASED ON BUTYL RUBBER

2020 ◽  
Vol 3 (2) ◽  
pp. 36-45 ◽  
Author(s):  
O. Tarasova ◽  
Yu. Yurkin ◽  
A. Toroschin
Keyword(s):  
Phenol Formaldehyde ◽  
Dynamic Properties ◽  
Dynamic Mechanical Properties ◽  
Mechanical Analysis ◽  
Strength Properties ◽  
Butyl Rubber ◽  
Polymer Materials ◽  
Polymer Mixture ◽  
Damping Properties ◽  
Dynamic Mechanical

this work is devoted to the problem of developing vibration-damping polymer materials with high damping properties in a wide temperature range. The study of the effect of modifying additives on the strength, damping, adhesive and cohesive properties of a butyl rubber composite is the aim of this work. The task is to identify the actual temperature, frequency, dynamic and mechanical characteristics of a composite material based on butyl rubber depending on the type and concentration of resins. The key methods for studying this problem is the dynamic mechanical analysis method, aimed at obtaining information about changes in the dynamic properties of polymer materials (bond strength with metal when peeling samples of composites, determining the flow resistance of samples, determining the migration of plasticizer). Due to the established experimental dependences, it was found that the addition of resins (3% by weight) in the composition based on butyl rubber leads to an increase in the damping properties of composite materials, and an increase to (4.25% by weight) leads to their decrease. It was established that the obtained filled mixtures with a high damping peak and good adhesive and strength properties are mixtures with the addition of alkyl phenol-formaldehyde resins.

Dynamic and creep analysis of polyvinyl alcohol based films blended with starch and protein

2018 ◽  
Vol 39 (1) ◽  
pp. 35-47 ◽  
Author(s):  
Naman Jain ◽  
Vinay K. Singh ◽  
Sakshi Chauhan
Keyword(s):  
Polyvinyl Alcohol ◽  
Moisture Absorption ◽  
Viscoelastic Behavior ◽  
Mechanical Analysis ◽  
Cross Linking ◽  
Mechanical And Thermal Properties ◽  
Blend Films ◽  
Creep And Recovery ◽  
Degradation Temperature ◽  
Creep Analysis

Abstract The present study focuses on the fabrication and analyses of polyvinyl alcohol (PVA) based films blended with polymers, such as starch and protein. The aim is to improve the moisture absorption, solubility, mechanical and thermal properties of PVA by blending it with various polymers. The thermal cross-linking of the films has been studied by heating the films at 120°C for 4 h. The result shows that PVA was completely soluble in water, while post-blending solubility and moisture absorption of blended films decreased. The tensile strength of blended films was significantly higher (4%–29%) as compared to neat PVA, while thermally cross-linked films showed much higher strength (8%–174%). Blended films were characterized using Fourier transform infrared spectroscopy (FTIR) to confirm the formation of hydrogen bonds. Thermogravimetric analysis showed the increase in degradation temperature post-blending as compared to neat PVA. The viscoelastic behavior of the material as well as glass transition temperature was studied using dynamic mechanical analysis. Creep and recovery behavior were examined to study the effect of stress and temperature on creep strain. The biodegradability of the blended films was increased post-blending. This study showed that PVA based blend films can replace non-biodegradable plastics and hence are necessary for the development of environmentally friendly materials.

scholarly journals Surface Modification of Carbon Fibers by Grafting PEEK-NH2 for Improving Interfacial Adhesion with Polyetheretherketone

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 778 ◽  
Author(s):  
Elwathig. Hassan ◽  
Tienah. Elagib ◽  
Hafeezullah Memon ◽  
Muhuo Yu ◽  
Shu Zhu
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Carbon Fibers ◽  
Interfacial Adhesion ◽  
Mechanical Analysis ◽  
Interlaminar Shear Strength ◽  
Thermoplastic Composites ◽  
Negative Effects ◽  
Covalent Bonds ◽  
Interlaminar Shear

Due to the non-polar nature and low wettability of carbon fibers (CFs), the interfacial adhesion between CFs and the polyetheretherketone (PEEK) matrix is poor, and this has negative effects on the mechanical properties of CF/PEEK composites. In this work, we established a modification method to improve the interface between CFs and PEEK based chemical grafting of aminated polyetheretherketone (PEEK-NH2) on CFs to create an interfacial layer which has competency with the PEEK matrix. The changed chemical composition, surface morphology, surface energy, and interlaminar shear strength were investigated. After grafting, the interlaminar shear strength (ILSS) was improved by 33.4% due to the covalent bonds in the interface region, as well as having good compatibility between the interface modifier and PEEK. Finally, Dynamic Mechanical Analysis (DMA) and Scanning Electron Microscopy (SEM) observation also confirmed that the properties of the modified CF/PEEK composites interface were enhanced. This work is, therefore, a beneficial approach towards enhancing the mechanical properties of thermoplastic composites by controlling the interface between CFs and the PEEK matrix.

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