Evaluation of thermal and physical properties of PMMA/PMVEMA-ES blends as organic coating

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shameer Hisham ◽  
Hairul Anuar Tajuddin ◽  
Norazilawati Muhamad Sarih ◽  
Nur Zarith Diana Diana Zakaria ◽  
Zul Hazrin Zainal Abidin ◽  
...  

Purpose In this work, the blends of poly(methyl methacrylate), PMMA and poly(methyl vinyl ether-alt-maleic acid monoethyl ester), PMVEMA-ES are studied as organic coatings to evaluate the impact of intermolecular hydrogen bonding on the physical and thermal characteristics of the prepared coatings. Design/methodology/approach PMMA (Mw = 120,000 g mol-1) was chosen as our binder material. Due to the low adhesion property of PMMA on polar substrates, it was blended with PMVEMA-ES, which contains polar –COOH groups, to improve the adhesion and thermal properties of the coatings by forming intermolecular hydrogen bonds. A cross-hatch adhesion test was carried out to evaluate the adhesion strength of different ratios of PMMA/PMVEMA-ES blends as coatings. In addition, changes in the glass-transition temperature, Tg as the composition varies were studied using Differential Scanning Calorimetry, DSC. Then, glossiness and hiding power tests were also conducted to evaluate the physical properties of the prepared coatings. Findings Upon a closer look at the DSC results, it was found that blends consisting of 12.5, 25.0 and 87.5 wt. % PMMA were completely compatible due to the presence of only a single Tg in their thermograms. Other blend compositions showed two distinct Tgs, indicating partial compatibility. Furthermore, the addition of PMVEMA-ES caused the Tg of PMMA to shift to lower temperatures, a strong indication of intermolecular hydrogen bonding interactions between the two components. From the cross-hatch adhesion results, the addition of PMVEMA-ES improved the adhesion properties of PMMA coating, except for blends consisting of 62.5 and 75.0 wt. % PMMA possibly due to the partial incompatibility between the two components. These findings were further corroborated with the results of glossiness and hiding power measurements. The superior result was seen for the blend consisting of 12.5 wt. % PMMA with strong adhesion property, high glossiness, compatibility and high translucency. Practical implications PMVEMA-ES can potentially be used as an adhesion promoter in PMMA-based coating formulations. Originality/value This is the first report on the properties of PMMA/PMVEMA-ES blends as coatings.

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Darya Ewaznezhad Fard ◽  
Saeideh Gorji Kandi ◽  
Marziyeh Khatibzadeh

Purpose The purpose of this study is to investigate the changes in the performance of ink formulations caused by the addition of compounds that improve the ink’s physical properties to achieve an optimum formulation for inkjet printing, because of the importance and simplicity of this method. Design/methodology/approach Ink samples were formulated using Acid Red 14 as ink colorant, different percentages of polymeric compounds including polyvinyl alcohol (PVA), polyvinylpyrrolidone and Carboxy methyl cellulose (CMC) as viscosity modifier compounds and surfactant as the surface tension enhancer. Formulated samples were adjusted in terms of fluid physical properties e.g. viscosity, density and surface tension, and the effect of used compounds on the improvement of both physical and colorimetric properties such as viscosity, surface tension, colorimetric coordinates and lightfastness has been evaluated to achieve the optimum printing inks to be printed on three different substrates. Findings The experimental observations showed that CMC was the most compatible compound as the viscosity modifier as its viscosity value was in the printable range of 2–22 cP. Moreover, a flow-curve test was applied to the ink samples and their Newtonian behavior was approved. Based on the spectrophotometric test results of printed samples, the samples containing PVA provided acceptable lightfastness in comparison to other ink samples on every used substrate. Originality/value An optimum relation between colorimetric coordinates of the printed samples and ink formulation could be considered and achieved.


2008 ◽  
Vol 37 (1) ◽  
pp. 21-27
Author(s):  
H. Satapathy ◽  
A.K. Banthia

PurposeThe purpose of this paper is to synthesise, characterise and study polymerisation kinetics of novel 4‐nonylphenylmethacrylate (NPMA) polymer.Design/methodology/approachNew methacrylic monomer, 4‐NPMA with a pendant nonylphenyl group was synthesised and characterised using various characterisation techniques. The free radical polymerisation kinetics study was done with the help of differential scanning calorimetry data.FindingsThe average heat of polymerisation (ΔHp) was found to be 685.43 J/g. Activation energy (Ea) of 95.86 kJ mol−1 and frequency factor of (A) 3.4 × 104 min−1 was obtained using Kissinger method. The thermogravimetric analysis of the polymer in nitrogen reveals that it possesses very good thermal stability in comparison to alkyl methacrylates due to presence of pendant nonylphenyl group.Research limitations/implicationsNew methacrylic monomer, 4‐NPMA was synthesised by reacting nonylphenol dissolved in methyl ethyl ketone (MEK) with methacryloyl chloride in the presence of triethylamine as a base. Polymerisation of 4‐NPMA was carried out in MEK using benzoyl peroxide (BPO) as initiator under nitrogen atmosphere. The kinetics study of NPMA monomer with 1.1 wt% BPO was reported for evaluation of kinetic parameters by employing the Kissinger equation.Practical implicationsThis is a simple and easy method of modification of methacrylate ester with phenyl groups to obtain a polymer of enhanced properties.Originality/valueThis is a novel method for enhancing the thermal as well as surface adhesion properties of methacrylate polymers which finds several applications in surface coatings and adhesives.


2021 ◽  
Vol 9 ◽  
Author(s):  
Priya Verma ◽  
Anubha Srivastava ◽  
Karnica Srivastava ◽  
Poonam Tandon ◽  
Manishkumar R. Shimpi

The pharmaceutical cocrystal of caffeine-citric acid (CAF-CA, Form II) has been studied to explore the presence of hydrogen bonding interactions and structure-reactivity-property relationship between the two constituents CAF and Citric acid. The cocrystal was prepared by slurry crystallization. Powder X-ray diffraction (PXRD) analysis was done to characterize CAF-CA cocrystal. Also, differential scanning calorimetry (DSC) confirmed the existence of CAF-CA cocrystal. The vibrational spectroscopic (FT-IR and FT-Raman) signatures and quantum chemical approach have been used as a strategy to get insights into structural and spectral features of CAF-CA cocrystal. There was a good correlation among the experimental and theoretical results of dimer of cocrystal, as this model is capable of covering all nearest possible interactions present in the crystal structure of cocrystal. The spectroscopic results confirmed that (O33-H34) mode forms an intramolecular (C25 = O28∙∙∙H34-O33), while (O26-H27) (O39-H40) and (O43-H44) groups form intermolecular hydrogen bonding (O26-H27∙∙∙N24-C22, O39-H40∙∙∙O52 = C51 and O43-H44∙∙∙O86 = C83) in cocrystal due to red shifting and increment in bond length. The quantum theory of atoms in molecules (QTAIM) analysis revealed (O88-H89∙∙∙O41) as strongest intermolecular hydrogen bonding interaction with interaction energy −12.4247 kcal mol−1 in CAF-CA cocrystal. The natural bond orbital analysis of the second-order theory of the Fock matrix highlighted the presence of strong interactions (N∙∙∙H and O∙∙∙H) in cocrystal. The HOMO-LUMO energy gap value shows that the CAF-CA cocrystal is more reactive, less stable and softer than CAF active pharmaceutical ingredients. The electrophilic and nucleophilic reactivities of atomic sites involved in intermolecular hydrogen bond interactions in cocrystal have been demonstrated by mapping electron density isosurfaces over electrostatic potential i.e. plotting molecular electrostatic potential (MESP) map. The molar refractivity value of cocrystal lies within the set range by Lipinski and hence it may be used as orally active form. The results show that the physicochemical properties of CAF-CA cocrystal are enhanced in comparison to CAF (API).


2019 ◽  
Vol 32 (2) ◽  
pp. 93-103
Author(s):  
Kamila Piotrowska ◽  
Feng Li ◽  
Rajan Ambat

Purpose The purpose of this paper is to investigate the decomposition behavior of binary mixtures of organic activators commonly used in the no-clean wave flux systems upon their exposure to thermal treatments simulating wave soldering temperatures. The binary blends of activators were studied at varying ratios between the components. Design/methodology/approach Differential scanning calorimetry and thermogravimetric analysis were used to study the characteristics of weak organic acid (WOA) mixtures degradation as a function of temperature. The amount of residue left on the surface after the heat treatments was estimated by gravimetric measurements as a function of binary mixture type, temperature and exposure time. Ion chromatography analysis was used for understanding the relative difference between decomposition of activators in binary blends. The aggressivity of the left residue was assessed using the acidity indication gel test, and effect on reliability was investigated by DC leakage current measurement performed under varying humidity and potential bias conditions. Findings The results show that the typical range of temperatures experienced by electronics during the wave soldering process is not sufficient for the removal of significant activator amounts. If the residues contain binary mixture of WOAs, the final ratio between the components, the residue level and the corrosive effects depend on the relative decomposition behavior of individual components. Among the WOA investigated under the conventional wave soldering temperature, the evaporation and removal of succinic acid is more dominant compared to adipic and glutaric acids. Practical implications The findings are attributed to the chemistry of WOAs typically used as flux activators for wave soldering purposes. The results show the importance of controlling the WOA content and ratio between activating components in a flux formulation in relation to its tendencies for evaporation during soldering and the impact of its residues on electronics reliability. Originality/value The results show that the significant levels of flux residues can only be removed at significantly higher temperatures and longer exposure times compared to the conventional temperature range used for the wave soldering process. The potential corrosion issues related to insufficient flux residues removal will be determined by the residue amount, its composition and ratio between organic components. The proper time of thermal treatment and careful choice of fluxing formulation could ensure more climatically reliable product.


2017 ◽  
Vol 737 ◽  
pp. 248-255 ◽  
Author(s):  
Tae Hee Kim ◽  
Dae Yeon Kim ◽  
Choong Sun Lim ◽  
Bong Kuk Seo

The preparation of high performance epoxy composites for industrial applications has been extensively researched. In this report, we study the change in physical properties and reaction kinetics between epoxy resin and curing agents of similar geometry. For the experiments, celloxide 2021P, an epoxy resin having low viscosity, was blended with three different curing agents: methylhexahydropthalic acid, methyltetrahydropthalic acid, and 5-norbornene-2, 3-dicarboxylic anhydride. The amount of 1, 2-dimethylimidazole catalyst was controlled, and the highest heat flow temperature (Tpeak) was observed at around 145 °C. The impact on reaction kinetics relative to the change in heating rate was studied with differential scanning calorimetry (DSC) for each of the curing agents. The glass transition temperature (Tg) of each composition was measured with a second DSC cycle. The prepared epoxy compositions were thermally cured in a metallic mold to provide pure epoxy resins without fillers. Finally, the flexural strengths of these resins were compared to each other. The authors believe that insights into choosing an appropriate epoxy binder are useful when it comes to the overall preparation of high performance polymer composites.


1971 ◽  
Vol 75 (21) ◽  
pp. 3313-3316 ◽  
Author(s):  
K. R. Lindfors ◽  
S. H. Opperman ◽  
M. E. Glover ◽  
J. D. Seese

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 704
Author(s):  
Krystel Pélissier ◽  
Dominique Thierry

It is well known that the surface state (cleanliness, composition) of galvanized steel prior to the application of an organic coating is an important parameter. The surface state will affect the adhesion properties of the complete system and therefore will also impact its corrosion resistance and its tendency to blistering. Before the application of a pretreatment layer, galvanized steel strips are normally alkaline cleaned. This step is known to remove the native oxide film formed on hot dip galvanized steel after processing and appears as one of the most important steps to study the impact of the surface properties on the performance of painted systems. This study focused on making use of the cleaning step to input a variability on the surface composition (mainly surface concentration of aluminum) and evaluate its consequence(s) on the performance of a complete paint system. The results showed that, a variability in terms of surface aluminum concentration could be achieved by the cleaning step and that signs of performance improvement in terms of adhesion and tendency to blistering were spotted with a low content of aluminum at the surface.


Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 201 ◽  
Author(s):  
Wei-Chen Su ◽  
Fang-Chang Tsai ◽  
Chih-Feng Huang ◽  
Lizong Dai ◽  
Shiao-Wei Kuo

In this study, we enhanced the toughness of epoxy resin by blending it with the diblock copolymer poly(ethylene oxide–b–ε-caprolactone) (PEO-b-PCL) with a benzoxazine monomer (PA-OH) as the thermal curing agent. After thermal curing, Fourier transform infrared spectroscopy revealed that intermolecular hydrogen bonding existed between the OH units of the epoxy–benzoxazine copolymer and the C–O–C (C=O) units of the PEO (PCL) segment. Differential scanning calorimetry and dynamic mechanical analysis revealed that the glass transition temperature and storage modulus of the epoxy–benzoxazine matrix decreased significantly upon increasing the concentration of PEO-b-PCL. The Kwei equation predicted a positive value of q, consistent with intermolecular hydrogen bonding in this epoxy–benzoxazine/PEO-b-PCL blend system. Scanning electron microscopy revealed a wormlike structure with a high aspect ratio for PEO-b-PCL as the dispersed phase in the epoxy–benzoxazine matrix; this structure was responsible for the improved toughness.


2002 ◽  
Vol 57 (3-4) ◽  
pp. 184-188 ◽  
Author(s):  
P. A. Kumar ◽  
V. G. K. M. Pisipati ◽  
A. V. Rajeswari ◽  
S. Sreehari Sastry

New liquid crystalline compounds involving intermolecular hydrogen bonding between mesogenic p-n-alkoxybenzoic acids (nABA) (where n denotes the alkoxy carbon number varying from propylto decyl- and dodecyl-) and p-aminobenzonitrile (ABN) are synthesized. The thermal and phase behaviour of these materials is studied by Thermal Microscopy and Differential Scanning Calorimetry. Adetailed IR spectral investigation in solid and solution states confirms the formation of H-bonding between cyano and −COOH groups of ABN and nABA, respectively. Comparative thermal analyses of both free p-n alkoxybenzoic acids and H-bonded complexes suggest the induction of smectic-G phase in all the complexes.


2015 ◽  
Vol 45 (4) ◽  
pp. 595-605 ◽  
Author(s):  
Ana Carolina Conti-Silva ◽  
Renata Ferreira Roncari

Purpose – The purpose of this paper is to substitute wheat flour by passion fruit peel flour in Brazilian honey bread (pão de mel), with evaluation of the breads’ sensory features, chemical composition and physical properties. Design/methodology/approach – Honey breads with wheat flour (standard) and with replacement of this ingredient by 10 to 50 per cent passion fruit peel flour were produced. Two sensory tests were applied, to identify how different formulations with passion fruit peel flour were when compared to the standard formulation, and also the acceptability of the products. The selected honey breads, through sensory results, were evaluated regarding to chemical composition and physical properties. Findings – Formulations with 10 and 20 per cent substitution were the least different to formulations with only wheat flour, and were as acceptable as the wheat flour sample. Physical and chemical characteristics of breads with 10 and 20 per cent passion fruit peel flour were similar; however, honey bread with 20 per cent passion fruit peel flour had higher fibre content, ash quantity and hardness value; a lower specific volume; and a different colour from the wheat flour sample. Practical implications – This study offers an opportunity to food industries through utilization of an agro-industrial by-product on the formulation of a Brazilian traditional product. Originality/value – This study presents the feasibility of using an agro-industrial by-product to Brazilian honey bread, enhancing the nutritive value of this product and reducing the impact of passion fruit peel flour on the environment.


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