Polymerization of N-methyl B-methyl amino borazine

2011 ◽  
Vol 31 (5) ◽  
Author(s):  
Hicham Moutaabbid ◽  
Mohammed Moutaabbid
Keyword(s):  
Condensation Reaction ◽  
Thermal Polymerization ◽  
Decomposition Temperature ◽  
Size Exclusion ◽  
Cross Link ◽  
Scanning Calorimetry ◽  
High Quality ◽  
Link Density ◽  
Exclusion Chromatography ◽  
Cross Link Density

Abstract A large quantity of high-quality poly[N-methyl B-methyl amino borazine] was synthesized via a solventless method from the monomer 1,3,5-trimethyl-2,4,6-tri(methyl amino)borazine. The thermal polymerization profile was investigated with differential scanning calorimetry (DSC), Fourier transform infrared (FTIR), size exclusion chromatography (SEC), gas chromatography, and mass spectrometry. A polymerization mechanism involving the condensation reaction of two –N(H)CH3 groups releasing methylamine was proposed and compared with the literature. As a result of cross-linking via the amino­methyl moiety, the cured polymer exhibited a molecular weight Mn of 790 g mol-1, glass transition temperature of 64°C, high cross-link density, and thermal stability with a decomposition temperature of 165°C. Functionalized poly[N-methyl B-methyl amino borazine] with chemical stability was fully characterized by 1H, 13C, 11B nuclear magnetic resonance, FTIR, DSC, and SEC analyses. Ultraviolet absorption spectra evidenced changes in the structure of the aforementioned oligomers.

Reclaiming of waste guayule natural rubber vulcanizate—reclaim rubber for green tire applications: An approach for sustainable development

2018 ◽  
Vol 51 (3) ◽  
pp. 193-210 ◽  
Author(s):  
Soumyajit Ghorai ◽  
Dipankar Mondal ◽  
Sawar Dhanania ◽  
Santanu Chattopadhyay ◽  
Madhusudan Roy ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Polymer Chains ◽  
Cross Link ◽  
Scanning Calorimetry ◽  
Infrared Study ◽  
Differential Scanning Calorimetry Study ◽  
Link Density ◽  
Cross Link Density ◽  
Silica Dispersion ◽  
The Fourier Transform

This article illustrates the reclaiming of guayule natural rubber (GNR) vulcanizate by bis[3-(triethoxysilyl)propyl] tetrasulfide (TESPT), and as-grown reclaim rubber facilitates the silica dispersion in GNR product application without adding any coupling agent. This article deals with the performance evaluation of silica-filled revulcanizates with promising application in green tire. The extent of reclaiming was monitored through the measurement of sol content, cross-link density, Mooney viscosity, and degree of reclaiming. The differential scanning calorimetry study was carried out to evaluate the fraction of immobilized polymer chains and its dependence on cross-link density of the vulcanizates. The Fourier transform infrared study and also sulfur analysis independently indicate the attachment of the fragmented TESPT with the polymer chain and cross-link bonds. The study of mechanical properties clearly shows that in revulcanized GNR, the optimum property is achieved when reclaiming time is set for 40 min. The effect of reclaiming time on dynamic mechanical behavior such as storage modulus and loss tangent was studied. The scanning electron microscopy studies show the coherency and homogeneity of silica-filled revulcanize rubber with reclaiming time.

Effects of acrylonitrile content on thermal characteristics and thermal aging properties of carbon black-filled NBR composite

2020 ◽  
pp. 009524432094124
Author(s):  
Young Seok Lee ◽  
KiRyong Ha
Keyword(s):  
Thermal Aging ◽  
Aging Process ◽  
Elastic Recovery ◽  
Thermal Characteristics ◽  
Butadiene Rubber ◽  
Cross Link ◽  
Scanning Calorimetry ◽  
Aging Properties ◽  
Link Density ◽  
Cross Link Density

In seal applications, thermal characteristics and thermal aging properties of rubber are essential factors in determining the applicable temperature range and lifetime of the seal. In this study, thermal characteristics and thermal aging properties of the acrylonitrile butadiene rubber composite in response to the acrylonitrile (ACN) content were investigated. Thermal stability, glass transition temperature ( T g), and dynamic property were determined by thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis, respectively. The results showed that T g, thermal decomposition temperature, and tan δ were increased as the ACN content increased. To investigate the thermal aging properties of the composite, the composite was subjected to an accelerated thermal-oxidative and thermal aging process at 100°C for 168 h. The aged composites were evaluated by investigating the change in cross-link density, mechanical properties, and elastic recovery. The change in the chemical functional group was also studied using attenuated total reflectance Fourier transform infrared spectroscopy. The results indicate that subjecting the composite to thermal-oxidative and thermal aging process decreased the elongation at break and elastic recovery, while the cross-link density, Shore A hardness, and 100% modulus were increased. All of the properties were also dependent on the ACN content as well as the aging conditions.

scholarly journals Influence of e-Beam Irradiation on the Physicochemical Properties of Poly(polyol Succinate-co-Butylene Succinate) Ester Elastomers

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3196
Author(s):  
Marta Piątek-Hnat ◽  
Kuba Bomba ◽  
Jakub Pęksiński ◽  
Agnieszka Kozłowska ◽  
Jacek G. Sośnicki ◽  
...  
Keyword(s):  
Succinic Acid ◽  
Thermomechanical Analysis ◽  
Resonance Spectroscopy ◽  
Cross Link ◽  
Scanning Calorimetry ◽  
Water Contact ◽  
Butylene Succinate ◽  
Link Density ◽  
Static Tensile ◽  
Cross Link Density

The purpose of this research was synthesis and electron beam modification of novel ester elastomers consisting of sugar alcohol–succinic acid block and butylene glycol–succinic acid block. Four different alditols were used in the synthesis—sorbitol, erythritol, xylitol, and glycerol. The materials were irradiated with doses of 50, 100, and 150 kGy in order to determine which dose is the most beneficial. As expected, irradiation of the materials has led to the cross-link density becoming higher and improvement of the mechanical properties. Additionally, the materials were also sterilized in the process. The great advantage of elastomers described in the paper is the fact that they do not need chemical cross-linking agents or sensitizers in order to undergo radiation modification. The following tests were performed on cross-linked poly(polyol succinate-co-butylene succinate) elastomers: quasi-static tensile test, determination of cross-link density, differential scanning calorimetry (DSC), dynamic thermomechanical analysis (DMTA), wettability (water contact angle), and Fourier transform infrared spectroscopy (FTIR). In order to confirm successful synthesis, prepolymers were analyzed by nuclear magnetic resonance spectroscopy (1H NMR and 13C NMR).

scholarly journals Influence of the Cross-Link Density on the Rate of Crystallization of Poly(ε-Caprolactone)

Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 902 ◽  
Author(s):  
Igor Sedov ◽  
Timur Magsumov ◽  
Albert Abdullin ◽  
Egor Yarko ◽  
Timur Mukhametzyanov ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Crystallization Process ◽  
Polymer Chains ◽  
Degree Of Crystallinity ◽  
Cross Link ◽  
Scanning Calorimetry ◽  
Covalent Bonds ◽  
Fast Scanning Calorimetry ◽  
Link Density ◽  
Cross Link Density

Cross-linked poly(ε-caprolactone) (PCL) is a smart biocompatible polymer exhibiting two-way shape memory effect. PCL samples with different cross-link density were synthesized by heating the polymer with various amounts of radical initiator benzoyl peroxide (BPO). Non-isothermal crystallization kinetics was characterized by means of conventional differential scanning calorimetry (DSC) and fast scanning calorimetry (FSC). The latter technique was used to obtain the dependence of the degree of crystallinity on the preceding cooling rate by following the enthalpies of melting for each sample. It is shown that the cooling rate required to keep the cooled sample amorphous decreases with increasing cross-link density, i.e., crystallization process slows down monotonically. Covalent bonds between polymer chains impede the crystallization process. Consequently, FSC can be used as a rather quick and low sample consuming method to estimate the degree of cross-linking of PCL samples.

Boron nitride for modification of rubber based on isoprene elastomer

2020 ◽  
pp. 105-112
Author(s):  
K. S. Zhansakova ◽  
E. N. Eremin ◽  
G. S. Russkikh ◽  
O. V. Kropotin
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Gradual Increase ◽  
Physical And Mechanical Properties ◽  
Curing Time ◽  
Cross Link ◽  
Start Time ◽  
Link Density ◽  
Cross Link Density ◽  
Isoprene Rubber

The work studies vulcanization characteristics of elastomers based on isoprene rubber filled with carbon black N330 and boron nitride (BN). The influence of the boron nitride (BN) concentration on technological, dynamic, physical and mechanical properties of elastomers has been researched. The application of boron nitride for producing rubber with good properties has been considered. With a gradual increase of the inert filler BN concentration up to 35%, a decrease in the curing rate by 33% and polymer cross-link density by 26% is observed. Moreover, the start time of vulcanization increases by almost 300%, the optimal curing time by 200%.

Mechanical and structural consequences of associative dynamic cross-linking in acrylic diblock copolymers

2021 ◽  
Author(s):  
Jacob Ishibashi ◽  
Ian Pierce ◽  
Alice Chang ◽  
Aristotelis Zografos ◽  
Bassil El-Zaatari ◽  
...  
Keyword(s):  
Viscoelastic Properties ◽  
Diblock Copolymers ◽  
Microphase Separation ◽  
Network Connectivity ◽  
Ethyl Acrylate ◽  
Cross Linking ◽  
Cross Link ◽  
Block Polymers ◽  
Link Density ◽  
Cross Link Density

<p>The composition of low-T<sub>g</sub> <i>n</i>-butylacrylate-<i>block</i>-(acetoxyaceto)ethyl acrylate block polymers is investigated as a strategy to tune the properties of dynamically cross-linked vinylogous urethane vitrimers. As the proportion of the cross-linkable block is increased, the thermorheological properties, structure, and stress relaxation evolve in ways that cannot be explained by increasing cross-link density alone. Evidence is presented that network connectivity defects such as loops and dangling ends are increased by microphase separation. The thermomechanical and viscoelastic properties of block copolymer-derived vitrimers arise from the subtle interplay of microphase separation and network defects.</p><div><br></div><p></p>

A study on the kinetics and thermal properties of polystyrene/diatomite nanocomposites prepared via in situ ATRP

2018 ◽  
Vol 33 (2) ◽  
pp. 180-197 ◽  
Author(s):  
Khezrollah Khezri ◽  
Yousef Fazli
Keyword(s):  
Molecular Weight ◽  
In Situ Polymerization ◽  
Structural Characteristics ◽  
Nitrogen Adsorption ◽  
Linear Increase ◽  
Size Exclusion ◽  
Scanning Calorimetry ◽  
Morphological Studies ◽  
Exclusion Chromatography

Pristine mesoporous diatomite was employed to prepare polystyrene/diatomite composites. Diatomite platelets were used for in situ polymerization of styrene by atom transfer radical polymerization to synthesize tailor-made polystyrene nanocomposites. X-Ray fluorescence spectrometer analysis and thermogravimetric analysis (TGA) were employed for evaluating some inherent properties of pristine diatomite platelets. Nitrogen adsorption/desorption isotherm is applied to examine surface area and structural characteristics of the diatomite platelets. Evaluation of pore size distribution and morphological studies were also performed by scanning and transmission electron microscopy. Conversion and molecular weight determinations were carried out using gas and size exclusion chromatography, respectively. Linear increase of ln ( M0/M) with time for all the samples shows that polymerization proceeds in a living manner. Addition of 3 wt% pristine mesoporous diatomite leads to an increase of conversion from 72% to 89%. Molecular weight of polystyrene chains increases from 11,326 g mol−1 to 14134 g mol−1 with the addition of 3 wt% pristine mesoporous diatomite; however, polydispersity index values increases from 1.13 to 1.38. Increasing thermal stability of the nanocomposites is demonstrated by TGA. Differential scanning calorimetry shows an increase in glass transition temperature from 81.9°C to 87.1°C by adding 3 wt% of mesoporous diatomite platelets.

Mechanical behavior of poly(methyl methacrylate)-based ionogels

Soft Matter ◽  
2014 ◽  
Vol 10 (40) ◽  
pp. 7993-8000 ◽  
Author(s):  
Mingyu Li ◽  
Jianyu Li ◽  
Hui Na ◽  
Joost J. Vlassak
Keyword(s):  
Methyl Methacrylate ◽  
Mechanical Behavior ◽  
Fracture Energy ◽  
Cross Link ◽  
Poly Methyl Methacrylate ◽  
Link Density ◽  
Cross Link Density ◽  
The Cross ◽  
The Ideal

We demonstrate that the fracture energy of ionogels correlates inversely with the cross-link density. The behavior of ionogels is well captured by the ideal elastomeric gel model.

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