Polyamide Resin Research Articles

Overview of Polyamide Resins and Composites : A Review

Polyamide (PA) is one of five engineering plastic materials which has good mechanical properties and competitive price compared to other engineering plastics and it has various applications including in the areas of automotives, electronics and aerospace industry. Even though PA market grows fast compared to other engineering plastics, it has few organized literatures regarding researches and applications. In this paper, we review overall background, characteristics, formulation, current market trends and technology development of PA resins and their composites.

Isolation, purification, and identification of the main phenolic compounds from leaves of celery (Apium graveolens L. var. dulce Mill./Pers.).

We developed a simple and meaningful preparative method for the separation and purification of the main phenolic compounds from the leaves of celery (Apium graveolens L. var. dulce Mill./Pers.) and we established an accurate and specific analytical method for the identification of the main phenolic compounds from celery leaves. The crude extract from celery leaves was prefractioned by polyamide resin to enrich the phenolic compounds. They were then purified further by preparative high-performance liquid chromatography, and seven main phenolic compounds were obtained: including chlorogenic acid, luteolin 7-O-β-d-apiofuranosyl(1→2)-β-d-glucopyranoside, luteolin 7-O-β-d-glucopyranoside, apiin, chrysoeriol 7-O-β-d-apiofuranosyl(1→2)-β-d-glucopyranoside, luteolin 7-O-[β-d-apiofuranosyl(1→2)-(6''-O-malonyl)]-β-d-glucopyranoside, and apigenin 7-O-[β-d-apiofuranosyl(1→2)-(6''-O-malonyl)]-β-d-glucopyranoside. Their purities were measured by using high-performance liquid chromatography, and their chemical structures were confirmed using UV spectrophotometry, ultra high performance liquid chromatography with quadrupole time-of-flight tandem mass spectrometry, and NMR spectroscopy. Our studies indicate that preparative high-performance liquid chromatography combined with polyamide resin is a simple and meaningful preparative method for the separation and purification of phenolic compounds from the leaves of celery or other plants, and the use of UV spectrophotometry, ultra high performance liquid chromatography with quadrupole time-of-flight tandem mass spectrometry, and NMR spectroscopy is an accurate and specific analytical method for the identification of phenolic compounds.

Adsorption characteristics of adsorbent resins and antioxidant capacity for enrichment of phenolics from two-phase olive waste.

In this study, the adsorption properties of nine resins including polyamide resin (30-60), polyamide resin (60-100) AB-8, S-8, D-101, NKA-9, NKA-II, XDA-1 and XDA-4 for enrichment phenolics of the olive waste were investigated. XDA-1 and NKA-II were chosen for further study due to their outstanding adsorption and desorption capacity. XDA-1 and NKA-II had similar adsorption and desorption behaviors for phenolics of olive waste. The adsorption mechanism could be better explained by pseudo second-order kinetics model and Freundlich isotherm model, and the adsorption processes were spontaneously and exothermic. The experiment of gradient elution were carried out through treated XDA-1 resins column, the result indicated the total phenolics were mainly obtained from the 40% and 60% ethanol fraction. The order of antioxidant capacity by DPPH , ABTS+ radical and FRAP assay was similar with the content of phenolics from fraction elution. The compositions of phenolics from different elution fractions were determined by reversed phase-HPLC-DAD method. Gallic acid, hydroxytyrosol, tyrosol and ferulic acid were the major constituent in the fraction elute, and the content of hydroxytyrosol reached to the 41.69mg/g. The above results revealed the synergistic effects of the different phenolics contribute to the antioxidant capacity.

Construction of NIRS-based process analytical system for production of salvianolic acid for injection and relative discussion

Currently, near infrared spectroscopy (NIRS) has been considered as an efficient tool for achieving process analytical technology(PAT) in the manufacture of traditional Chinese medicine (TCM) products. In this article, the NIRS based process analytical system for the production of salvianolic acid for injection was introduced. The design of the process analytical system was described in detail, including the selection of monitored processes and testing mode, and potential risks that should be avoided. Moreover, the development of relative technologies was also presented, which contained the establishment of the monitoring methods for the elution of polyamide resin and macroporous resin chromatography processes, as well as the rapid analysis method for finished products. Based on author's experience of research and work, several issues in the application of NIRS to the process monitoring and control in TCM production were then raised, and some potential solutions were also discussed. The issues include building the technical team for process analytical system, the design of the process analytical system in the manufacture of TCM products, standardization of the NIRS-based analytical methods, and improving the management of process analytical system. Finally, the prospect for the application of NIRS in the TCM industry was put forward.

Preparation and characterization of polyester amide resin derived from Nigerian soya bean oil and its performance evaluation as binder for surface coatings

Polymeric systems based on polyesteramides (PEA) are high performance materials, which combine the useful properties of polyester and polyamide resins. In this work, a new modified polyesteramide resin was prepared and evaluated as binder for surface coating.The resin was synthesised by the reaction of N,N-bis-(2-hydroxyethyl) soya bean oil fatty acid amide (HESFAA) as a source of the polyol and as preservative against microbiological attack, with phthalic anhydride as the ingredient source of the polybasic acid. The measured acid value of the resin was found to be 7 mg KOH/g, which indicates the complete formation of the resin. The structure of the resin was confirmed by FT-IR spectral studies. The results show that the modification enhances both phyisco-mechanical and chemical properties of the PEA. From the analyses carried out, the synthesized resin could be suitable as binder for different types of paint. Keywords: Binder, Phthalic anhydride, Polyester amide, Soya bean oil fatty acid

Increased bending rigidity of wool fabric imparted by hybrid organic-inorganic sol–gel coatings

Hybrid organic–inorganic coatings prepared by the sol–gel method can impart desirable properties to textiles, but may adversely affect properties such as bending rigidity. This study investigated the causes of increased bending rigidity. Woven wool fabric was pad coated with formulations of methyltriethoxysilane (MTES) and Hercosett polyamide resin, examined by scanning electron microscopy, and the bending rigidities were determined. MTES coatings of up to 3.0% solids on mass of wool did not impart unacceptable bending rigidity. The coatings were not uniform on the fiber surfaces, and the increases in fabric bending rigidity could be partially attributed to inter-fiber bonding. In addition, the coatings “pinned” the edges of the cuticle scales, making individual fibers harder to bend. These effects are only weakly dependent on the Young's moduli of the coating materials.

Apigenin-7-O-β-D-glycoside isolation from the highly copper-tolerant plant Elsholtzia splendens.

Elsholtzia splendens (Lamiaceae) is a copper-tolerant plant species growing on copper deposits in the south of China. Chromatographic separation of n-BuOH extracts from the flowering aerial biomass afforded apigenin-7-O-β-D-glycoside, using macroporous resin, Sephadex™ LH-20 gel, polyamide resin as well as preparative high-performance liquid chromatography (P-HPLC) columns. Chemical structure was elucidated using HPLC/ESI-MS (electrospray ionization-mass spectrometry), Fourier transform infrared (FTIR), and (1)D- and (2)D-nuclear magnetic resonance (NMR). Apigenin-7-O-β-D-glycoside could be the post-harvesting product from E. splendens biomass.

Large-Scale Ultrasonic Fabrication of White Fluorescent Carbon Dots

We first used oligomer polyamide resin as carbon source to prepare carbon dots (CDs) that can emit white fluorescence via one step ultrasound at room temperature. We have had a further understanding in the surface morphology and chemical characteristics of the CDs by performing TEM, XPS, XRD, FT-IR, and Raman spectroscopy. It has been found that such carbon dots have good dispersion, low crystallinity, rich surface functional groups, and easy large-scale production. The quantum yield of the white fluorescent CDs was further enhanced from 3.3% to 28.3% by adding a silane coupling agent as a co-passivating agent and conducting ultrasonic treatment. We successfully prepared white-light-emitting diodes using these carbon dots as light conversion materials. To further broaden the applications of white fluorescent carbon dots, we employed the as-prepared CD solution as ink to prepare luminescent patterns, along with favorable versatile effect.

Screening method for the onset of bonding of molten polyamide resin layers to continuous fiber reinforced laminate sheets

Thermoplastic polymer composites (TPC) with multiple fabric layers of continuous fiber reinforcement are laminate sheets designed to be thermally stamped and overmolded leading to low cycle times and thus high volume composite parts. Injection over-molding is one way to combine the high processability of thermoplastic melts with the less processable TPC sheets, for complex part making. To simulate the adhesion development during processes like over-molding, a non-isothermal screening method for bonding molten polyamide (PA) to a solid TPC surface has been developed and applied to evaluate differences in the threshold temperatures for good bond formation as a function of TPC matrix composition. Pure PA66 and aromatic high temperature nylons (PPA) in addition to miscible PPA blends comprising different ratios of PA66, were used as TPC matrices, and retain most of the very high melting point of 100% PPA. We have devised experiments to address two critical aspects: The first is to develop a screening test that probes very short timescales relevant to practical part making. The second is to investigate various miscible semi-crystalline blend ratios as matrices for the TPC where both blend species are crystalline. This allows us to explore a practical improvement of a lower required bonding temperature without substantially decreasing the high melting point of the PPA. DSC was also used to correlate the various blend melting transitions with the temperature required for the onset of bonding. The interfaces are shown to develop high strength partly because of substantial surface melting of certain blend components of the initially solid TPC, and this quickly allows interpenetration and inter-diffusion across the interface, which then crystallizes and strengthens during cooling.

Amorphous polyamide coating resins from sugar-derived monomers

In this article, the synthesis of bio-based polyamides for powder coating applications and their evaluation in a solventborne coating system are reported. The M n values of the resins were between 3000 and 4000 g mol−1 and the resins displayed T g values from 60 to 80°C. Both amine and carboxylic acid functionalities (total ~0.6 mmol g−1) were introduced for curing purposes. The resins were cured with triglycidyl isocyanurate (TGIC) or N,N,N′,N′-tetrakis(2-hydroxyethyl)adipamide (Primid XL-552). The curing reaction was followed using rheology which indicated that TGIC achieved higher reaction rates and higher gel contents. The DSC analysis of the cured disks showed that all cured samples were amorphous as is desired for the targeted coating application. The resins required a curing temperature higher than 150°C. Aluminum panels were coated using a solventborne approach and the coatings were cured at 180°C during 1 h. Dewetting was observed on all panels. Network formation was adequate for an amine-functional resin cured with TGIC as indicated by solvent resistance testing. In conclusion, the developed bio-based polyamide resins are promising materials to be used as binder resins in powder coating applications.

Preparation of Wogonin from Radix Scutellariae and its Inhibitory Effects on the Growth of HepG2 Cells

Context: Wogonin as one of the main bioactive components of Radix Scutellariae is promising for cancer therapy. However efficiency of preparation of wogonin is low. Objective: The present study was aimed to develop an efficient method for preparative separation of high-purity wogonin from Radix Scutellariae and evaluate its inhibitory effects on HepG2 cell proliferation. Materials and Methods: Radix Scutellariae was hydrolyzed in water (pH 5) for 12 h and then extracted with 95% ethanol. The extractum was separated with 30-60 mesh polyamide resin column. Fraction with wogonin was subjected to highspeed countercurrent chromatography (HSCCC). Human HepG2 cells were cultured in different concentrations of prepared wogonin in vitro. Cell proliferation was evaluated by MTT. Results: 525 mg of wogonin was obtained from 50 g of raw Radix Scutellariae, with a purity of 98.7%. Wogonin (12.5, 25, 50, 100 and 200 μM) dose-dependently inhibited the growth of HepG2 cells. Conclusion: An efficient method for preparing high-purity wogonin was established. Keywords: Extraction, high-speed countercurrent chromatography, polyamide resin column, preparation, Radix Scutellariae , wogonin.

Polyamide resin for paper wet strength improvement

In order to enhance consumer properties of the tissue paper, effective chemicals, namely the epichlorohydrin-modified polyamide resin of different manufacturers, are selected for paper strength improvement in dry and wet conditions. The environmentally friendly Kymene 25X-Cel resin made in the USA is characterized by the highest efficiency. Also, the given resin appeared the most economic in production. Expenditure amounted to 2 kg per ton of paper. Fiber composition for paper production based on bleached sulphate softwood pulp – 40 %, bisulphate softwood pulp – 20 %, bleached sulphate hardwood pulp – 40 %, ground to 27–32°SR is developed. Such ratio of fiber semi-products provides the highest consumer properties of paper. It is found that the Kymene 25X-Cel resin should be added to the paper pulp after grinding of cellulose fibers and diluted with water prior to introduction. Under these conditions, the highest efficiency of the resin is achieved. Paper samples with different contents of the epichlorohydrin-modified polyamide Kymene 25X-Cel resin (0.2–0.8 % of absolutely dry fiber), which were compared with the paper sample made without the resin are made. It is determined that 0.6–0.8 % of absolutely dry fiber is an effective resin content in the paper composition. It allows achieving the necessary paper strength of 9.3–9.6 % for the developed fiber composition, which provides basic operational properties of finished products.

Solvent free synthesized MnFe2O4@polyamid resin as a novel green nanohybrid for fast removing Congo red

The development of environmental friendly techniques for synthesizing material is a main interest in green chemistry, as the absence of organic solvents in the synthetic routs is a major presage for realizing green ways. Based on this viewpoint, a solvent free green rout has been employed to prepare magnetic MnFe2O4 nanoparticles and MnFe2O4 reinforced polyamide resin. MnFe2O4 nanoparticles was synthesized through mixing the solid reagents with NaOH at room temperature. Polyamide and magnetic resin were synthesized through heating the mixture of citric acid, p-phenylenediamine and MnFe2O4 at 155°C. The products were characterized with XRD, VSM, FT - IR, FE - SEM and TEM techniques. Characterization analysis revealed that the magnetic nanoparticles were less than 20nm in diameter, and polyamide possessed stacked sheet structure with thickness in nano scale. Prepared magnetic resin was employed as a green adsorbent for removing Congo red from aqueous solution. Equilibrium was obtained within one minute as well as the sorbent showed a superior adsorption capacity of 1000mgg−1.

A5052アルミニウム合金－ポリアミド樹脂の接着性に及ぼすアルミニウムへの表面処理の影響

A5052アルミニウム合金－ポリアミド樹脂の接着性に及ぼすアルミニウムへの表面処理の影響

A polyamide resin based method for adsorption of anthocyanins from blackberries

A polyamide resin was successfully employed for the purification of blackberry anthocyanins and this proved to be an efficient and low-cost method.

THE EFFECT OF TWO PACKING TECHNIQUES ON ADAPTATION OF RESIN DENTURE BASE MATERIALS

Background: Acrylic resin denture bases undergo dimensional changes during polymerization. Injection molding techniques are reported to reduce these changes and thereby improve physical properties and adaptation of denture bases. The aim of this study was to compare denture baseadaptation processed by conventional and injection-molding techniques. Materials and Methods: Twenty one accurate denture bases with the same dimension were fabricated and divided into three groups. For the first group, sevenpolymethyl methacrylate denture bases were made using conventional compression moulding technique and for the other two groups, two different injection mouldingunits were used to produce seven polyamide bases (thermo-plasticized) and seven polymethyl-methacrylate (PMMA) bases (themo-polymerized). The adaptation accuracy was examined using universal measuring microscope. The gap between the resin base and stone cast was measured at posterior palatal area at five points, corresponding to the right and left residual ridge crests, the midline, and the right and left marginal limits of the flanges. Results: Injection molded bases showed significant lower total gap scores at the crest and the palate compared to the conventional compression molded ones. However, there was no statistically significant difference between both groups at the vestibular gap. Injection molded poly-amide resin denture bases showed significant difference compared to PMMA injected molded ones. Conclusion: Injection moulded polyamide resin has superior dimensional accuracy and adaptation compared to conventional pressure packed or injection moulded PMMA resin

Nghiên cứu chế tạo lớp phủ bảo vệ bo mạch điện tử trên cơ sở nhựa Epoxy biến tính bằng cao su Polysulfide lỏng

This paper presents some results in studying and producing a coating to protect printed circuit board from tropical environmental impact. We have tested the protective ability of the coating based on epoxy resin ED-20 and low-molecular weight polyamide resin L-20 modified by liquid polysulfide rubber NVB-2. The testing data has shown that the coating has high mechanical, environmental and electrical durability.

Brazilian cerrado biome plant extract bank screening in inflammatory disease and cancer enzymes

A total of 702 extracts from the Brazilian Cerrado Biome Plant Extract Bank of the University of Brasília, Brazil – produced from 95 species representing 40 families were tested for inhibitory activity against p38 kinase and MALT1 protease. These enzymatic targets are implicated in inflammatory disease and B-cell lymphoma, respectively. Data from both assays were compared directly in order to identify those extracts with specificity for p38. This resulted in the identification of 13 extracts from 6 plant families (Annonaceae, Flacourtiaceae, Hippocrateaceae, Sapindaceae, Sapotaceae and Malpighiaceae) that showed specific p38 inhibition. These extracts were then eluted through polyamide resin to remove polyphenolic compounds. Two extracts (Pouteria gardneri and P. ramiflora) lost their activity, but an additional extract maintained enzymatic inhibition following polyamide and continues to be investigated. Here we report initial results on the identification of natural product inhibitors of p38.

Preparation and toxicological evaluation of methyl pyranoanthocyanin

Anthocyanins are increasingly valued in the food industry for their functional properties and as food colorants. The broadness of their applications has, however, been limited by the lack of stability of these natural pigment extracts in a number of food systems. The potential application of pyranoanthocyanins, anthocyanin derivatives with better stability conferred by the added pyran ring, as a food ingredient was determined. Methylpyranoanthocyanin (MPA) was prepared from reaction of acetone and anthocyanin extracts from red grapes. Reaction products were sequentially purified with polyamide resin, TSK gel resin and semi-preparative HPLC to a purity level >98%. Cytoprotective influence tests of the purified MPA indicated its significant protective effect against H2O2 induced MRC-5 cell damage. Results of evaluations of possible acute toxicity effects on MPA-fed mice, including macro and microscopic assessments, support the conclusion of a non-toxic effect of MPA, and its potential safe use as a food additive.

Biodegradable Blends Based on Polyhydroxybutyrate: Structure and Water Diffusion

Abstract. The present article focuses on the study of novel blends based on poly(3-hydroxybutyrate) (PHB) and polymers with different hydrophilicity (PELD, PA and PVA).Polymer blends were produced from five ratios of PHB/PELD in an effort to regulate theresistance to hydrolysis or (bio)degradation through the control of water permeability. Therelation between the water transport and morphology (TEM data) shows the impact of polymercomponent ratio on the regulation of water flux in hydrophobic matrix. To elucidate the role ofhydrophilicity of second component presenting in the PHB blends, we studied the PHB/PAblends where PA is the polyamide resin composed of statistical copolymer ofhexamethyleneadipinate and -caprolactam in ratio 1:1. The complex of techniques includingDCS and FTIR-imaging (for T-scale) demonstrates the interaction between PHB and PA inthe temperature ranges of crystallization and melting. The general approach based on Flory-Huggins equation is presented as the way to choose the pairs of compatible or partly compatiblepolymers. Mechanical characteristics and water permeability of films on the basis of PVA-PHB mixtures depending on their composition were investigated. It was shown that the additiveof PHB increments water permeability of a polymeric matrix, but at major dosage of PHB thepermeability of films can be reduced because of ability of PHB to fix water. It was determinedby DSC, polarization IR-spectroscopy, WAXS and SAXS-experiments that there is a connectionbetween structural architecture of films at crystalline (or at molecular) level with waterpermeability and mechanical performances. It was shown that the decreasing of strength offilms occurs at PHB concentration more than 20 % (for PVA-PHB mixtures). Blending PHBwith PA and PVA could be a simple and effective method to design new matrices for drugdelivery in medicine, while the same procedure applied for PHB-PELD system with betterresistance to hydrolysis and lower price than initial PHB could be used as novel bioerodiblepackaging materials.Key words: biodegradable polymer blends, polyhydroxybutyrate, polyamide, polyvinylalcohol, polyethylene, structure, water diffusion.IntroductionThe blending of semicrystalline biodegradableand friendly environmental thermoplastics such asbacterial poly(3-hydroxybutyrate) [PHB] with oneof the cheapest packing or industrial polymer suchas low-density polyethylene [PELD] and withhydrophilic polyamide [PA], polyvinylalcohole[PVA] is a perspective tool to obtain novel materialswith combined characteristics of the originalcomponents along with economic advantages formaterial performance.The families of biodegradable polymers,namely poly--hydroxyacides (PLA, PGA, and