Types Of Resins Research Articles

High performance epoxy cresol novolac photocuring resins: Tailoring performance through adamantane modification

With the development of high-frequency communication technology, higher heat resistance and lower dielectric constant requirements have been put forward on solder resins. The introduction of rigid groups is expected to meet these requirements. Adamantane has an alicyclic hydrocarbon with a large spatial structure, which can be introduced into solder resist resins to improve their overall performance. In this paper, 3-amino-1-adamantanol (AD) was introduced into the epoxy cresol novolac (EOCN). Firstly, amino reacted with epoxy groups, followed by the reaction of anhydride with hydroxyl groups. The carboxyl groups introduced after the anhydride reaction can further react with glycidyl methacrylate (GMA). Finally, a new type of photocuring resin was obtained by adjusting the type of anhydride. Intriguingly, when the anhydride is maleic anhydride (MA), the higher crosslinking density and the tuning of the flexible molecular chain densification during the curing process allow the resin to possess high Tg and high storage modulus properties. As a consequence, the optimized UV-curable film has a strong storage modulus (2615.84 MPa), excellent heat resistance (Tg: 181.57 °C), and low dielectric constant (2.7 at 1 Hz). It also provides an effective strategy for the design and fabrication of high-performance EOCN-based photocuring materials.

Effect of surface finish and resin cement on the bond strength to CAD-CAM ceramics for interim resin-bonded prostheses

Statement of problemResin-bonded prostheses, including interim resin-bonded prostheses, are effective in preserving tooth structure compared with other types of fixed dental prostheses for the replacement of missing teeth. However, loss of retention remains a notable concern with these types of prostheses. PurposeThe purpose of this in vitro study was to investigate the influence of glass-ceramic type, resin type, and surface finish on the shear bond strength (SBS) to the CAD-CAM ceramics used to fabricate interim resin-bonded prostheses. Material and methodsEighty 10×2-mm glass-ceramic disks were fabricated by using a diamond saw (IsoMet 1000), 40 from feldspathic porcelain blocks (Vita Mark II) and 40 from lithium disilicate blocks (IPS e.max CAD). Half of the specimens in each group were left with a dull or matte surface finish after cutting, while the other half were glazed with an add-on glaze (VitaAkzento Plus Glaze Spray and IPS e.max CAD Glaze Spray, respectively). The disks were mounted in acrylic resin, and each group was subdivided into 2, with 1 receiving a photopolymerized resin cement (RelyX Veneer) and the other receiving a flowable composite resin (Filtek Supreme Ultimate Flow) to form 2.38×2-mm cylinders. SBS was determined using a universal testing machine (Instron 4411) in accordance with the International Organization for Standardization (ISO) 29022:2013 standard, and failure modes were analyzed by using a stereomicroscope with ×40 magnification. The data were analyzed with a 3-way analysis of variance and Tukey post hoc analysis. The chi-squared test was used to analyze the failure mode (α=.05 for all tests). ResultsCeramic type, resin type, and surface finish significantly impacted SBS (P<.001, P=.003, P<.001, respectively). Lithium disilicate showed higher SBS than feldspathic porcelain, and flowable composite resin exhibited higher SBS than resin cement. Glazed surfaces displayed lower SBS compared with the dull or matte surfaces. The combinations among the 3 materials also impacted SBS (P=.03). In addition, the combinations between ceramic type and surface finish affected SBS (P<.001), regardless of resin cement type. No other combinations affected the SBS (P>.05). The mode of failure was different among the groups (P<.001). In comparison with all other groups, cohesive failures were most prevalent in feldspathic porcelain with a dull or matte surface finish, regardless of the resin type used. ConclusionsThe SBS to glass-ceramics was influenced by ceramic material, resin cement type, and surface finish. Flowable composite resin showed higher SBS than resin cement. A dull or matte surface finish exhibited greater bond strength than a glazed surface. Lithium disilicate had higher SBS than feldspathic porcelain.

Numerical analysis of the porous structure of spherical activated carbons obtained from ion-exchange resins

This paper presents the results of an analysis of the porous structure of spherical activated carbons obtained from cation-exchange resin beads subjected to ion exchange prior to activation. The study investigated the effects of the type of cation exchange resin, the concentration of potassium cations in the resin beads and the temperature of the activation process on the adsorption properties of the resulting spherical activated carbons. The numerical clustering-based adsorption analysis method and the quenched solid density functional theory were used to analyse the porous structure of spherical activated carbons. Based on original calculations and unique analyses, complex relationships between preparation conditions and the porous structure properties of the obtained spherical activated carbons were demonstrated. The results of the study indicated the need for simultaneous analyses using advanced methods for the analysis of porous structures, i.e., the numerical clustering-based adsorption analysis method and the quenched solid density functional theory. This approach allows a reliable and precise determination of the adsorption properties of the materials analysed, including, among other things, surface heterogeneities, and thus an appropriate selection of production conditions to obtain materials with the expected adsorption properties required for a given industrial process.

New type of coatings combining invisibility and high power laser protection function

With the rapid development of laser technology, the protection of high-energy lasers has received increasingly widespread attention. The current laser protection methods only have single function, and do not consider the detection technology. Based on this, this article proposes a bilayer coating system that combines invisibility and high energy laser protection performance. For surface layer, four types of carbon materials were used as fillers and two types of resins were used as base materials. For the bottom layer, both YSZ block and YSZ plasma sprayed coating were used. The results show that the carbon material in surface layer react with oxygen rapidly under laser irradiation conditions, achieving the rapid transition from invisible state to laser protection state. This bilayer coating has simple process and low cost, leading to great application value. Meanwhile, this method also provides inspiration for the design and preparation of other multifunctional coatings.

Adsorption and desorption characteristics of flavonoids from white tea using macroporous adsorption resin

White tea contains the highest flavonoids compared to other teas. While there have been numerous studies on the components of different tea varieties, research explicitly focusing on the flavonoid content of white tea remains scarce, making the need for a good flavonoid purification process for white tea even more important. This study compared the adsorption and desorption performance of five types of macroporous resins: D101, HP20, HPD500, DM301, and AB-8. Among the tested resins, AB-8 was selected based on its best adsorption and desorption performance to investigate the static adsorption kinetics and dynamic adsorption-desorption purification of white tea flavonoids. The optimal purification process was determined: adsorption temperature 25 °C, crude tea flavonoid extract pH 3, ethanol concentration 80%, sample loading flow rate and eluent flow rate 1.5 BV/min, and eluent dosage 40 BV. The results indicated that the adsorption process followed pseudo-second-order kinetics. Under the above purification conditions, the purity of the total flavonoids in the purified white tea flavonoid increased from approximately 17.69 to 46.23%, achieving a 2.61-fold improvement, indicating good purification results. The purified white tea flavonoid can be further used for nutraceutical and pharmaceutical applications.

Research new type of cation-exchange resin for waste water treatment

This article presents the studies obtaining and research new polycondensation type phosphoric cation-exchange resin. The conditions for the phosphorylation of this polymer were selected from the experiments accumulated in relation to the phosphorylation reactions of low- and high-molecular compounds. The resulting polymer had an exchange capacity for a 0.1 N NaOH solution – 5,5-5,6 mEq/g and contained 16,5% phosphorus. Based on the studies carried out, the optimal conditions for the synthesis of the styrene-furfural polymer are assumed to be: the reaction temperature is 90°C, the concentration of the ZnCl2 catalyst is 0.07 mol per mole of furfural, and the molar ratio of styrene to furfural is 1:1. There was studied an interaction of the cation exchanger in Na- and H-forms with solutions of salts of copper sulfate, nickel, cobalt, sodium chloride, calcium and uranyl nitrate. In order to elucidate the mechanism of sorption of the cations of these metals, were taken the IR-spectra of the cation exchanger in the H- and Na- form, saturated with copper ions. The less dissociated phosphoric acid groups, the stronger hydrogen bond forms phosphoryl oxygen with OH-groups. Therefore, it can be expected that as the cation exchanger is saturated with sodium, the maximum of the band corresponding to the phosphorus-oxygen bond vibrations will slightly shift to longer wavelengths as a result of the destruction of the weaker hydrogen bond.

Study of the influence of tack resins on elastomeric formulations and applied evaluation methodologies

In this study, we examined the impact of eight distinct types of tack resins sourced from diverse origins (phenol-formaldehyde: SP – 1068, CRJ – 418, Koresin and SRF – 1501; hydrocarbons: Unilene A – 90 and Plastack RB 809; coumarone and breu) in several elastomeric formulations. For this purpose, it was developed a simple, robust and easily reproducible tack test employing synthetic rubber to assess these formulations. The elastomeric compounds were characterized by attenuated total reflectance Fourier transform infrared spectroscopy, rheometry, Mooney viscosity, crosslinking density by swelling in solvent, hardness, abrasion wear, tensile and tear strength, followed by tack tests. Overall, the formulations exhibited similar physical-mechanical properties. Regarding the tack test results, SP-1068 (phenol-formaldehyde) and Plastack RB 809 (hydrocarbon) resins demonstrated higher values, whereas the resorcinol-type phenol-formaldehyde presented a reduction of 10.7 %. Furthermore, interference from the functional groups in the resin’s chemical structure, difficulty in interacting with the matrix, and lower crosslink density were observed. In conclusion, the developed methodology proved satisfactory in yielding reliable and reproducible tack values.

Application of 3PHV60 Type Epoxy Resin for the Repair of Timber Structures

This article deals with the issue of repairing wooden structures with 3PHV60 type resin. The first step of the research was to understand the material properties of 3PHV60 resin. The information provided by the resin manufacturer and the tests based on fracture tests have greatly contributed to the proper study of the behaviour of this material. The use of resin for the repair of timber structures is discussed in relation to the type of internal forces.

Effect of Thermal Aging and Chemical Disinfection on the Microhardness and Flexural Strength of Flexible Resins

This article examines the effects of thermal aging and chemical disinfection on the microhardness and flexural strength of flexible resins. The influence of the resin type on the mechanical properties was also investigated. Two flexible resins, Deflex Classic SR and Deflex Supra SF, produced by the injection method, and a thermopolymerizable acrylic resin—ProBase Hot, produced by the flasking method, were subjected to 1000 cycles of thermal aging and three chemical disinfection protocols (n = 8), with daily immersion and during a recommended time, in Corega Whitening, Corega Oxygen Bio-Active, 2.5% sodium hypochlorite, and distilled water (control). Knoop microhardness and three-point flexural strength were evaluated. Data were analyzed using Wilcoxon, Mann–Whitney and Kruskal Wallis tests (α = 0.05). The results varied between 14.5 KHN and 80.1 MPa for ProBase Hot and 7.3 KHN for Deflex Classic SR and 52.5 MPa for Deflex Supra SF. Thermal aging reduced the microhardness of the flexible resins, but not their flexural strength. The microhardness of Deflex Classic SR was influenced by chemical disinfection with Corega Bio-active (p &lt; 0.001). The flexural strength of Deflex Supra SF was influenced by chemical disinfection with Corega Whitening (p &lt; 0.05). It can be concluded that chemical disinfection led to changes in the flexible resins and should be used with caution to maintain the mechanical properties of the resins. Flexible resins showed reduced resistance to physical and chemical environmental influences, which can affect their longevity.

Questionnaire Survey about Knowledge of Incremental Techniques in Composite Placement among Dentists in South India

Introduction: Dental composite resins are types of synthetic resins which are used in dentistry as restorative material or adhesives. Synthetic resins evolved as restorative materials since they were insoluble, esthetic, and insensitive to dehydration. Polymerization shrinkage is one of the major disadvantages in composites due to “c” factor. The aim of the study was to reduce this configuration, factor incremental techniques have been used. Several incremental techniques being followed by dentists. Incremental techniques are one of the most comfortable and qualitative technique which reduces “c” factor in composites. This is a questionnaire survey which assesses the most practiced incremental technique by various dentists.&#x0D; Materials and Methods: A questionnaire survey about the most popularly used incremental techniques being used in composite placement by several dentists has been analyzed.&#x0D; Results: Seventy percent of dentists are practicing incremental techniques in composite placement. The rest 30% of dentists are practicing bulk‑fill techniques. Of the dentists practicing incremental techniques, 71.43% are following oblique layering technique, 14.29% are following three‑site novel matrix, and the rest 14.29% are following successive cusp buildup technique.&#x0D; Conclusion: Of the three incremental techniques, oblique layering technique has many advantages such as allows easier Class II buildup, with proper proximal contact, and proximal smooth surfaces. Another advantage is that there is adequate light exposure for polymerization.&#x0D;

The filament winding method’s finishing process impact on high-fidelity specimens: homogenity of density, fiber volume fraction, outer surface roughness and tensile strength

Filament winding is a widely used method for producing tubes and pressure vessels from composite materials. However, overlapping of fibers during the winding process can lead to rough surface and increased voids in the finished product. To improve the quality of CFRP materials produced through filament winding, the structure is cured either at room temperature or in an oven with a controlled heat profile, depending on the type of resin used. Various finishing techniques, including shrink tape, compression molding, and vacuum compression molding, have been attempted to improve the quality of the specimen. Among these techniques, vacuum compression molding has been found to deliver the best results in terms of surface roughness, with average roughness (Ra) values of 0.35 μm in the fiber direction and 0.61 μm in the transverse direction. This level of roughness is comparable to that achieved through milling machine manufacturing. Moreover, this technique ensures uniformity in fiber composition and volume fraction, achieving a homogeneous density of 1364.49 kg/m3 and the highest fiber volume fraction of 63 %. As a result, remarkable mechanical attributes, such as a tensile strength of 926.07 MPa and a stiffness of 21.35 GPa, can be obtained. In addition, by utilizing various finishing techniques, the tensile strength of these properties can be increased by up to 80 %. CFRP is a versatile material with unique characteristics, and selecting appropriate finishing techniques such as vacuum compression molding can significantly enhance its overall quality and mechanical properties. However, one drawback of the filament winding method is the poor outer surface finish which can be improved by vacuum compression molding

New insights into brominated epoxy resin type WPCBs pyrolysis mechanisms: Integrated experimental and DFT simulation studies

Pyrolysis is a recycling technology for waste circuit boards (WPCBs) with a wide range of applications. In this research, the brominated epoxy resin (BER) type WPCBs were taken as the research object, and the optimal pyrolysis process parameters were determined. Combined with experiments and density functional theory (DFT) calculations, the pyrolysis gaseous generation pattern and product distribution of BER type WPCBs were analyzed, and the generation mechanism of phenol, bromide and other pyrolysis products was investigated in depth. The results of the study showed that the pyrolysis rate of WPCBs exceeded 95 % under optimal reaction conditions. In the initial phase of the pyrolysis of WPCBs, the BER's CO bonds and a portion of Ph-Br bonds will be broken, leading to the production of intermediates such propylene oxide, bisphenol A, isopropyl alcohol, tetrabromobisphenol A and HBr. Among them, propylene oxide can generate ethylene oxide through free radical reaction. In the second stage, intermediates such as bisphenol A undergo homolytic cleavage and radical addition to form phenols, bromides, alcohols, ketones and other pyrolysis products.

Tree-based machine learning approach to modelling tensile strength retention of Fibre Reinforced Polymer composites exposed to elevated temperatures

Fibre Reinforced Polymer (FRP) composites are susceptible to degradation at elevated temperatures. Accurate modelling of the tensile performance of FRP composites under high-temperature exposure is crucial for their structural integrity. In this study, tree-based models, namely, decision tree, M5P, and random forest methods, are utilised to model the impact of elevated temperatures on the tensile strength of composite materials. A database of 787 experimental results is established and processed to train and test the regression tree models. The exposure temperature, resin glass transition temperature, sample thickness/diameter, exposure duration, ambient cooling, fibre-to-resin ratio, fibre orientation, resin type, fibre type, and manufacturing process were considered as the main parameters affecting the tensile strength retention (TSR) of FRP composites after exposure to elevated temperatures. To improve the prediction performance of machine learning, Bayesian optimisation and 10-fold cross validation (CV) technique were used to train regression tree methods. The results demonstrated the accuracy of the developed models in predicting the TSR of the composites under elevated temperatures. Feature contribution analysis showed that the exposure temperature exerts the most significant impact on the TSR, with the glass transition temperature coming next in importance. These were followed by sample thickness, exposure duration, ambient cooling, fibre-to-resin ratio, and fibre orientation, respectively. Resin type, fibre type, and the manufacturing process had the least contributions to the observed variations in TSR. Examining the tensile strength retention of FRP composites at high temperatures enables the development of precise predictive models and design guidelines for their optimal use across industries.

Surface roughness of photoacrylic resin shapes obtained using PolyJet additive technology

The article presents the results of analyzing the surface roughness of samples manufactured using the PolyJet additive technology. Three types of photopolyacrylic resins were used in the production process of the test samples. The samples were measured using stylus and optical measurement methods. The presented research extends information on the surface roughness of resins used in the PolyJet 3D printing process. It is a starting point for further improvement of measurement procedures for polymer materials.

The effect of different curing distances on the microhardness of flowable bulk-fill composite materials

Background: The microhardness of a composite resin is a vital parameter that is used to determine its clinical behavior. Measuring the microhardness of a composite resin has been used as an indirect method to assess its degree of conversion and extent of polymerization. The purpose of this in vitro study was to evaluate the effect of three curing distances (0, 2, and 4 mm) on the microhardness of the top and bottom surfaces of three types of flowable bulk-fill composite resins (smart dentin replacement, Opus bulk fill flow, and Tetric N). Material and method: Sixty-three specimens from the three types of composite resins (n=21) were fabricated using Teflon mold with a 4mm depth and a 5 mm internal diameter and cured for 20 seconds. For each material, three subgroups were fabricated according to the position of the light curing tip from the top surface; at 0, 2, and 4 mm distances. Microhardness was measured using the Vickers test with a 50-g load for 15 seconds for the top and bottom surfaces of all the samples. Results: The microhardness values were decreased in the following order; 0mm &gt; 2mm &gt; 4mm curing tip distance, for both sides and Tetric N had the highest microhardness values. Significant differences in microhardness were recorded between the top and bottom surfaces for all the specimens (p&lt;0.05). Conclusion: Increasing the distances between the tip of the light cure and the surface of flowable bulk-fill resins can significantly decrease the microhardness of the bottom surfaces compared to the top surfaces.

Composite Resin Bond Strength to Zirconia and Base Metal Alloys Using Two Types of Intraoral Porcelain Repair Systems.

Objectives: This study aimed to evaluate the shear bond strength (SBS) of two repair composites (Crea.lign vs. PermaFlo) to a base metal alloy and zirconia ceramic. Materials and Methods: Sixty-four discs (12mm diameter, 1mm thickness) were fabricated using Wirobond base metal alloy and zirconia. They were then bonded with their respective composite resins (N=16) in each of the two porcelain chipping repair kit subgroups consisting of PermaFlo and Crea.lign. All specimens were stored in 37°C distilled water for 24 hours. Half of them were subjected to 10,000 thermal cycles (5-55°C, 30s). All specimens were tested for SBS with a universal testing machine. Failure types were analyzed using a digital camera. Analysis of the data was done by two-way ANOVA and Bonferroni post-hoc tests. Results: SBS was significantly affected by the type of composite resin. PermaFlo had a significantly higher SBS than Crea.lign to base metal alloy (P<0.001) and zirconia ceramic (P<0.001). Thermocycling decreased the SBS of both composites to base metal alloy (P<0.001) and zirconia (P<0.001). Conclusion: A universal adhesive could provide higher shear bond strength of zirconia and base metal alloy to composite resin than Crea.lign composite and the MKZ primer supplied by its manufacturer.

Evaluation of polymethyl-methacrylate and acetal denture base resins processed by two different techniques before and after nano-chlorohexidine surface treatment

BackgroundFlexible denture base polymers have gained popularity in modern dentistry however, their biofilm formation tendency, adversely affecting the oral tissue heath, remains a concern. Consequently, this study aimed to evaluate surface roughness and biofilm formation tendency of two types of denture base resins manufactured with two techniques before and after surface coating with chlorohexidine (CHX) NPs.Materials and methodsAcetal (AC) and Polymethyl-methacrylate (PMMA) resins manufactured by conventional and CAD/CAM methods were shaped into disk (10 X 10 X 1 mm). They were dipped for 8 h and 24 h in colloidal suspension prepared by mixing aqueous solution of CHX digluconate and hexa-metaphosphate (0.01 M). Surface roughness, optical density (OD) of microbial growth media and biofilm formation tendency were evaluated directly after coating. Elutes concentrations of released CHX were evaluated for 19 days using spectrophotometer. Three-way ANOVA and Tukey’s post-hoc statistical analysis were used to assess the outcomes.ResultsAC CAD/CAM groups showed statistically significant higher roughness before and after coating (54.703 ± 4.32 and 77.58 ± 6.07 nm, respectively). All groups showed significant reduction in OD and biofilm formation tendency after surface coating even after 19 days of CHX NPs release.ConclusionsBiofilm formation tendency was highly relevant to surface roughness of tested resins before coating. After CHX NPs coating all tested groups showed significant impact on microbial growth and reduction in biofilm formation tendency with no relation to surface roughness. Significant antimicrobial effect remained even after 19 days of NPs release and specimens storage.

Characterization and source apportionment of microplastics in Indian composts.

Microplastics (MP), small plastic particles under 5 mm, are pollutants known to carry heavy metals in ecosystems. Composts are a significant source of soil microplastics. This study examined MSW composts from Kochi and Kozhikode in India for microplastic concentrations and heavy metals' accumulation thereon. Microplastics were isolated using zinc chloride density separation, with Fenton's reagent used for organic matter oxidation. Resin types were identified using FTIR analysis that showed the presence of PE, PP, PS, nylon, PET, and allyl alcohol copolymer. In Kozhikode's compost, the average concentration of microplastics was 840 ± 30 items/kg, while Kochi had 1600 ± 111 items/kg, mainly polyethylene films. PE was the most prevalent resin, comprising 58.3% in Kozhikode and 73.37% in Kochi. Heavy metal analysis of MP showed significant concentrations of lead, cadmium, zinc, copper, and manganese adsorbed on the surface of microplastics. The concentrations of heavy metals in the MP before Fenton oxidation ranged from 1.02 to 2.02 times the corresponding concentrations in compost for Kozhikode and 1.23 to 2.85 times for Kochi. Source apportionment studies revealed that 64% of microplastics in Kozhikode and 77% in Kochi originated from single-use plastics. Ecological risk indices, PLI and PHI, showed that composts from both locations fall under hazard level V. The study revealed that compost from unsegregated MSW can act as a significant source of microplastics and heavy metals in the soil environment, with single-use plastics contributing major share of the issue.

Purification of the apple pomace polyphenol extract using adsorbent resin

AbstractPolyphenols from agro-industrial waste particularly of fruit origin are a reliable source of antioxidants and antimicrobials that can be used as natural food additives. Organic solvents play an important role in extracting the polyphenols, however, inefficiency in exerting bioactivity and interference with the organoleptic properties are among the reasons that hinder their use as food additives. These problems can be alleviated by purification. In this study, the effect of resin types and elution solvent for purification of the apple pomace extracts on total phenolic content (TPC) and antioxidants were investigated. Crude ethanolic extracts were purified using amberlite resins (XAD7HP and FPX66) in a glass column (25 × 310 mm). The sorption flow rate was 2 Bed volume (BV) per hour, rinse 2 BV per hour, and desorption was 2 BV per hour. Final wash and regeneration were each done by 2 BV per hour. Polyphenol content and antioxidant capacity were quantified spectrophotometrically using Folin-Ciocalteu and Ferric reducing ability of plasma (FRAP) assays respectively. Polyphenol recovery was 50% in XAD7HP (Lowest) using ethanol and 69% in FPX66 (Highest) using acetone. For the case of FRAP recovery, 76% (Lowest) was observed in FPX66 using ethanol while 93% (Highest) was observed in XAD7HP using acetone. Conclusively, FPX66 is the ideal resin for the purification of apple pomace extracts for enhancing antioxidant activity compared to XAD7HP. Further, acetone seems to be a good desorption solvent compared to ethanol.

Experimental study of distortion in side grinding of thin glass lenses

ABSTRACT The production of non-circular thin optical lenses involves initial processes such as circular cutting, grinding, lapping, and polishing. However, shaping the lenses into non-circular forms requires a final cutting process. This study focuses on addressing the distortion of BK7 thin glass parts during side grinding. Two clamping methods were examined to fix the components. The first method, commonly used in the industry, involves bonding the workpiece to a base using resin and subsequent machining, followed by separating the samples from the base by heating the resin. In contrast, this research explores an alternative approach using vacuum clamping. The components’ distortion was measured using an interferometer. The results show that the vacuum clamping method produces more uniform surface parameters for the polished components compared to the typical resin bonding method. Additionally, the analysis reveals that surface parameter variations are more pronounced during square side-grinding compared to circular side-grinding.