Solid Resin Research Articles

Термогравіметричні дослідження двокомпонентних епоксидних смол для виготовлення об’ємних етикеток

There was investigated the influence of temperature conditions on the stability of a polymer coating based on epoxy resins, which is used in the manufacture of volume labels by thermogravimetry.Objects of research were volumetric labels printed on a digital printing machine using transparent (glossy and matte) PVC films filled with different thicknesses of polymer coating. As a polymer coating, a soft and hard epoxy resin of 0.84 to 1.95 mm in thickness was used.The process of manufacturing volume labels included the preparation of an epoxy resin before applying a full-color printed image to the surface.Taking into account that for the production of volume labels we use multicomponent polymeric composite materials that are subject to heat treatment, for the study used thermogravimetric analysis, which involves studying the thermal stability of samples; with the registration of a similar signal of mass loss and thermal effects using a computer.It is proved that the sample of a volume label with soft epoxy resin demonstrates higher thermal stability. In the process of its heating during the studied temperature range there is less intensive mass lost compared with a label sample made of solid resin. The highs of exothermic effects of this sample shifted into higher temperatures range.Within the operating temperature range of 20–60° C samples of epoxy coating are heat resistant. In the process of heating the mass loss of samples does not exceed 0.5 % due to the allocation volatile compounds, which are present in them.The research allows to make the right choice of temperature conditions of polymer coatings formation based on of two-component epoxy resins in the manufacture of volume labels and conditions of their use.

Evaluating the use of amber in palaeoatmospheric reconstructions: The carbon-isotope variability of modern and Cretaceous conifer resins

Stable carbon-isotope geochemistry of fossilized tree resin (amber) potentially could be a very useful tool to infer the composition of past atmospheres. To test the reliability of amber as a proxy for the atmosphere, we studied the variability of modern resin δ13C at both local and global scales. An amber δ13C curve was then built for the Cretaceous, a period of abundant resin production, and interpreted in light of data from modern resins. Our data show that hardening changes the pristine δ13C value by causing a 13C-depletion in solid resin when compared to fresh liquid–viscous resin, probably due to the loss of 13C-enriched volatiles. Modern resin δ13C values vary as a function of physiological and environmental parameters in ways that are similar to those described for leaves and wood. Resin δ13C varies between plant species and localities, within the same tree and between different plant tissues by up to 6‰, and in general increases with increasing altitudes of the plant-growing site. We show that, as is the case with modern resin, Cretaceous amber δ13C has a high variability, generally higher than that of other fossil material. Despite the high natural variability, amber shows a negative 2.5–3‰ δ13C trend from the middle Early Cretaceous to the Maastrichtian that parallels published terrestrial δ13C records. This trend mirrors changes in the atmospheric δ13C calculated from the δ13C and δ18O of benthic foraminiferal tests, although the magnitude of the shift is larger in plant material than in the atmosphere. Increasing mean annual precipitation and pO2 could have enhanced plant carbon-isotope fractionation during the Late Cretaceous, whereas changing pCO2 levels seem to have had no effect on plant carbon-isotope fractionation. The results of this study suggest that amber is a powerful fossil plant material for palaeoenvironmental and palaeoclimatic reconstructions. Improvement of the resolution of the existing data coupled with more detailed information about botanical source and environmental growing conditions of the fossil plant material will probably allow a more faithful interpretation of amber δ13C records and a wider understanding of the composition of the past atmosphere.

Optical limiting effects of cyano substituted distyrylbenzene derivatives

Two liquid cyano substituted distyrylbenzene derivatives (P2 and P4) have been synthesized by incorporating two tetraethylene glycol groups into the prototype scaffolds of 2,5-bis(4-(diethylamino)styryl)terephthalonitrile (P1) and 2,2'-(1,4-phenylene)bis(3-(4-(diethylamino)phenyl)acrylonitrile) (P3), respectively, for increasing their solubilities in liquid and solid substrates. The linear photophysical properties, optical/thermal stabilities and optical limiting behaviors of P1–P4 have been investigated. Results show that both P2 and P4 have significant optical limiting behaviors on 800 nm laser pulses and high thermal stabilities. However, only P4 whose cyano groups substituted on the vinylene bond exhibits good optical stability, while P2 whose cyano groups substituted on the central phenylene ring presents gradual photobleaching under illumination. Through doping P4 into a solid epoxy resin, effective optical limiting devices to 800 nm pulsed laser are fabricated.

Preparation and characterization of ketonic polymer for coating applications

Abstract A systematic study has been performed to develop a synthetic resin from cyclohexanone by self–polymerization method in presence of a base catalyst. In addition, an effort has been made to characterize a product by analyzing its various physico–chemical properties such as hydroxyl content, iodine value, acid value, solubility, viscosity, adhesive strength, and average molecular weight. To investigate the effects of operating parameters on physico–chemical properties, reaction time was varied between 7 and 20 h, catalyst loading was varied between 0.05–0.4, and temperature was varied in the range of 90–160 °C. The extent of polymerization reaction increased with the increase of catalyst loading, reaction temperature and reaction time. A good quality resin was obtained when the reaction was performed in a closed reactor. The study confirmed that KOH offers better quality product than NaOH. The average molecular weight of the products lies in the range of 300–1200. It has been further observed that the adhesive strength of the solid resins is comparable with the commercial fivistick material. The article includes the development of mathematical model to find the product properties.

Microwave-Assisted Synthesis of Solid Epoxy Resins: Study of Molecular Weight by GPC and MALDI-TOF/MS

A new method of preparation of solid epoxy resins (SER) with desired epoxy-group content via an advanced process under microwave irradiation is presented together with the results of molecular weight measurements for narrow oligomeric fractions obtained from chromatographic separation of SER. All the measurements were performed using gel permeation chromatography (GPC) and matrix-assisted laser desorption ionization spectrometry–time of flight mass spectrometry (MALDI-TOF/MS). In the GPC analysis, two types of calibration were used: the first was a standard calibration based on polystyrene standards, while the second was done on the basis of a chromatograms of epoxy resins synthesized from bisphenol A (BPA) and diglycidyl ether of bisphenol A (EDBPA). On the basis of the MALDI-TOF analysis, it was assumed that the purity of starting materials, i.e., low molecular weight epoxy resin, clearly determined the structure of the SER. In order to obtain an SER with linear chain structures and an even number of po...

Effect of fabricated density and bamboo species on physical–mechanical properties of bamboo fiber bundle reinforced composites

Bamboo stems were subjected to a mechanical treatment process for the extraction of bamboo fiber bundles. The fiber bundles were used as reinforcement for the fabrication of high-performance composites with phenolic resins as matrix. The influence of fabricated density and bamboo species on physical–mechanical properties of bamboo fiber bundle reinforced composites (BFCs) was evaluated. The results revealed that BFCs with density of 1200 kg/m3 exhibited lower water absorption, better dimensional stability, and higher mechanical properties with comparison to those with lower density. The changes in microstructures of BFCs with respect to density gave evidence that the high performance of BFCs with high density was due to the almost complete collapse of bamboo lumens, which resulted in the formation of solid bamboo and thin resin films with water resistance ability. BFCs fabricated from five bamboo species all showed better properties compared to commercialized bamboo-based composites. However, significant differences in physical–mechanical properties of BFCs among bamboo species were also found. This may be attributed to the variations in anatomical structure and physical–mechanical properties among original bamboo species. From a practical production view, the effect of bamboo species on properties of BFCs should be properly taken into consideration.

Atmospheric corrosion evaluation of electrogalvanized, hot-dip galvanized and galvannealed interstitial free steels using accelerated field and cyclic tests

Abstract Three years of outdoor corrosion tests, accelerated with a saline solution spray, and SAE J2334 and GM 9540P accelerated corrosion tests of industrially coated electrogalvanized (GE), hot-dip galvanized (GI), galvanneal (GA) interstitial free steels were performed. The samples were industrially phosphatized and painted with a modified epoxy resin, polyester resin as a primer and a base coat, and a high solid acrylic resin varnish as a clear coat. The effect of the deposition process and zinc mass on atmospheric corrosion of galvanized interstitial free low-alloyed carbon steels was analyzed. The SAE J2334 test was more effective than the GM 9540P test in differentiating the lowest corrosion resistance of the hot dip galvanized steel among the galvanized steels studied. The duration of the accelerated field test played an important role in the steel performance rating. The parameter of maximum corrosion penetration was more efficient to distinguish the effect of the zinc mass on corrosion resistance of the galvanized steel samples evaluated using accelerated field tests.

Microencapsulation of 1-methylimidazole using solid epoxy resin: study on microcapsule residence time and properties of the system

In this study for the first time 1-methylimidazole was microencapsulated successfully by solid epoxy resin using solvent evaporation method. Fourier transform infrared spectroscopy, scanning electron microscopy, thermal gravimetric and differential scanning calorimetry were used for characterization of microcapsule and epoxy resin/microcapsule systems. The results revealed that although the solid epoxy shell was in contact with imidazole curing agent for a long time, it still remained as a thermoplastic. The chain length of the solid epoxy resin was grown in anionic polymerization process which led to an increase in the melting temperature from 64 to 78 °C. On the other hand, all epoxy functional groups of the shell did not participate in the curing reaction of resin with core curing agent of the microcapsule. The results showed that by increasing the residence time of the microcapsules, the number of epoxy groups of liquid epoxy decreased slightly but the rate of complex viscosity increase or the rate of curing reaction was increased and the cured epoxy system exhibited a single-phase morphology. On the other hand, in the presence of microcapsules the curing reaction of epoxy resin was successfully carried out and the curing temperature and the onset of viscosity increase or gel time at 120 °C were not more or less affected by sufficiently long contact time of epoxy and microcapsule.

A simple isotopic labeling method to study cysteine oxidation in Alzheimer's disease: oxidized cysteine-selective dimethylation (OxcysDML).

Cysteine is widely involved in redox signaling pathways through a number of reversible and irreversible modifications. Reversible modifications (e.g., S-glutathionylation, S-nitrosylation, disulfide bonds, and sulfenic acid) are used to protect proteins from oxidative attack and maintain cellular homeostasis, while irreversible oxidations (e.g., sulfinic acid and sulfonic acid) serve as hallmarks of oxidative stress. Proteomic analysis of cysteine-enriched peptides coupled with reduction of oxidized thiols can be used to measure the oxidation states of cysteine, which is helpful for elucidating the role that oxidative stress plays in biology and disease. As an extension of our previously reported cysDML method, we have developed oxidized cysteine-selective dimethylation (OxcysDML), to investigate the site-specific total oxidation of cysteine residues in biologically relevant samples. OxcysDML employs (1) blocking of free thiols by a cysteine-reactive reagent, (2) enrichment of peptides containing reversibly oxidized cysteine by a solid phase resin, and (3) isotopic labeling of peptide amino groups to quantify cysteine modifications arising from different biological conditions. On-resin enrichment and labeling minimizes sample handing time and improves efficiency in comparison with other redox proteomic methods. OxcysDML is also inexpensive and flexible, as it can accommodate the exploration of various cysteine modifications. Here, we applied the method to liver tissues from a late-stage Alzheimer's disease (AD) mouse model and wild-type (WT) controls. Because we have previously characterized this proteome using the cysDML approach, we are able here to probe deeper into the redox status of cysteine in AD. OxcysDML identified 1129 cysteine sites (from 527 proteins), among which 828 cysteine sites underwent oxidative modifications. Nineteen oxidized cysteine sites had significant alteration levels in AD and represent proteins involved in metabolic processes. Overall, we have demonstrated OxcysDML as a simple, rapid, robust, and inexpensive redox proteomic approach that is useful for gaining deeper insight into the proteome of AD.

Titanium oxide nanoparticle dispersions in a liquid monomer and solid polymer resins prepared by sputtering

A transparent nanocomposite resin with titanium oxide nanoparticles was prepared using a sputtering technique.

Postsynthetic modification of peptoids via the Suzuki-Miyaura cross-coupling reaction.

We developed a new method for modifying the side chains of peptoids on a solid phase resin, employing the palladium-catalyzed Suzuki-Miyaura cross-coupling reaction. Optimized conditions using Pd(PPh3 )4 and K2 CO3 in the presence of Buchwald's SPhos ligand provided a high conversion in the coupling reaction. The usefulness of this method was demonstrated by synthesis of a two pyrene-conjugated peptoid helix, which exhibited an interesting excimer formation.

Chiral dendrigraft polymer for asymmetric synthesis of isoquinuclidines

A copper complex of chiral modified dendrigraft amidoamine polymer with a pentaerythritol initiated polyepichlorohydrin core, PEN-G2, on a solid resin support is employed in the synthesis of isoquinuclidines via aza Diels–Alder reaction between cyclohexenone and imines.

ChemInform Abstract: Basic Concepts of Using Solid Phase Synthesis to Build Small Organic Molecules Using 2‐Chlorotrityl Chloride Resin

AbstractReview: 22 refs.

Enhancement of Rubber with 2,2,4-Trimethyl-1,2-Dihydro-Quinoline Polymer by the Addition of Catalyst of Solid Resin

Enhancement of Rubber with 2,2,4-Trimethyl-1,2-Dihydro-Quinoline Polymer by the Addition of Catalyst of Solid Resin

Synthesis of biodiesel from pongamia oil using heterogeneous ion-exchange resin catalyst

Biodiesel is a clean-burning renewable substitute fuel for petroleum. Biodiesel could be effectively produced by transesterification reaction of triglycerides of vegetable oils with short-chain alcohols in the presence of homogeneous or heterogeneous catalysts. Conventionally, biodiesel manufacturing processes employ strong acids or bases as catalysts. But, separation of the catalyst and the by-product glycerol from the product ester is too expensive to justify the product use as an automobile fuel. Hence heterogeneous catalysts are preferred. In this study, transesterification of pongamia oil with ethanol was performed using a solid ion-exchange resin catalyst. It is a macro porous strongly basic anion exchange resin. The process parameters affecting the ethyl ester yield were investigated. The reaction conditions were optimized for the maximum yield of fatty acid ethyl ester (FAEE) of pongamia oil. The properties of FAEE were compared with accepted standards of biodiesel. Engine performance was also studied with pongamia oil diesel blend and engine emission characteristics were observed.

English

A clear understanding on the fundamental mechanism in solid state self-healing resin system might significantly improve the optimization of healing performance. The focus of this study was to prove the diffusion (through thermal inter-diffusion) of a linear healing agent within the network matrix resin. The results had demonstrated that 45 to 21 percentage recoveries in fracture toughness (K1C) were observed within the third healing cycles of the healable resin. Based on the optical microscopy, scanning electron microscopy (SEM) and time-of-flight secondary ion mass spectrometry (ToF-SIM) analyst; the diffusion of healing agent was also demonstrated by the change in the morphology and chemical images of the healing agent on the fracture surface specimen, before and after healing process.

Development of technology to industrialise the production of 80000 MTPY epoxy resins

Purpose – The purpose of this paper is to establish a technology that is suitable for the production of the 80,000 MTPY series of epoxy resins on an industrial scale. Design/methodology/approach – This paper introduces the synthesis and processing of epoxy resins, including liquid epoxy resins (DGEBA) (E-51 and E-44), brominated bisphenol A-based epoxy resins (EX-23-80A), semisolid epoxy resins based on DGEBA (E-39D) and solid epoxy resins based on DGEBA (E-21). The study analyses the theoretical raw materials of epoxy resins per tonne, and lists an example of a distributed control system (DCS) to explain that the production process of 80,000 MTPY epoxy resins can be automated. Findings – A two-step method was used to produce either E-51 or E-44 sequentially in the pre-reactor, the reactor, the recycling kettle, refining kettle (1), the refining kettle (2) and the desensitizing kettle or the falling-film evaporator. An advancement process was adopted to manufacture EX-23-80A, E-39D and E-21 using E-51 as a raw material in the predominating kettle and the mixing kettle, the adding kettle (1) and the adding kettle (2), separately. All the processes were controlled automatically by DCS to yield the products. Originality/value – The results support the assertion that the technology developed by the authors ' company to produce 80,000 MTPY epoxy resins results in fewer side reactions and higher yield production.

The influence of Co/Sr and Fe/Sr driers on film formation of high solid alkyd coatings.

High solid (HS) alkyd resins with low amount of volatile organic compounds (VOC) were developed as the result of new VOC solvent directive that limit the amount of VOC in decorative paints. Due to specific chemical structure of HS alkyd resins and possible deterioration of some applicative properties the optimal combination of driers is an important subject of research. In our present work we studied the influence of iron (Fe) and cobalt (Co) surface driers with strontium (Sr) through drier on the film formation of HS alkyd coatings. The kinetics of autoxidation was analysed using FT-IR spectroscopy. Further, applicative properties like drying time and film hardness were examined. In the end, electrochemical impedance spectroscopy (EIS) was used to evaluate the quality of cured HS alkyd coating films after exposure in the humidity chamber. It was established that the addition of the Sr drier to surface driers accelerates the film formation process. As higher amounts of the Sr drier were added, final drying times were reduced and film hardness increased. The highest quality of cured films were observed for Co/Sr and Fe/Sr drier combination at 1:1 concentration ratio.

Visualization of Nanoparticles Behavior Introduced into Gas Flame Spraying

In a newly developed rod feeding gas flame process, solid resin rod including nanoparticles could be fed into a Rokide® flame gun successfully to create fine ceramics layers without micro cracks and pores applying for electric, magnetic and dielectric components. In this investigation, alumina particles of 170 nm in average diameter were dispersed into acrylic liquid resin at 40 % in volume fraction. The paste materials were injected into a brass mold of φ40×200 mm in inner dimension and thermal cured through heating at 120 °C for 60 min. Formed solid rods were fed into oxyacetylene gas flame coaxially by using the Rokide® spraying gun system. Sprayed particles were cached by water bath for microstructure observations by a scanning electron microscope and crystal phase analyses by an X-ray diffraction spectroscopy. Fine ceramics layer formations will be discussed systematically by the feeding speed of solid rods and gas flame condition of air pressure and oxygen pressure.

An enigmatic piece of amber in the Oligocene of the Assam-Arakan Basin (Eastern India)

Oil shale investigations in eastern India led to the discovery of an amber-filled vein within a rock that suffered sub-anchimetamorphic conditions whilst this material has never been found elsewhere than in low-grade diagenetic rocks. This discovery questions amber resistance to the increase of temperature and pressure. Our investigations indicate that a solid resin and incompletely polymerised amber are able to melt at a temperature of about 100–150°C. It appears that the studied amber nodule melts during the increase of the diagenetic grade. Chemical analysis demonstrates that such event do not modify the chemical signature of the amber and microstructure shows that cooling was probably slow, allowing the acquirement of microstructure similar to a normal amber piece excepted the high abundance of minute pyrite crystals.