Relationship between Degree of Polymeric Ionisation and Hydrolytic Degradation of Eudragit® E Polymers under Extreme Acid Conditions

The commercial copolymers Eudragit® E 100 and Eudragit® PO are widely used materials in the pharmaceutical field as coating systems. Such materials derived from amino-methacrylate groups under acidulated conditions may acquire an ionisable fraction or undergo hydrolytic degradation of the polymeric structure. This work focused on establishing the chemical, physical, and surface changes of two reprocessed polymeric materials, here named as EuCl-E-100 and EuCl-E-PO, which were obtained from the commercial Eudragit® E 100 and Eudragit® E PO, respectively. The commercial materials were exposed to extreme acid conditions, where the polymers were solubilised and subsequently dried by the refractance window method. The materials obtained were chemically characterised by potentiometric titration, nuclear magnetic resonance spectroscopy (1H NMR and 13C NMR) in one and two dimensions (COSY, HSQC, and HMBC), infrared spectroscopy, X-ray diffraction, and differential scanning calorimetry. Changes in the physical properties of the materials were evaluated through studies of flowability, compactability, and their ability to gain and lose humidity. Surface thermodynamic studies were carried out through contact angle measurements using the sessile drop method. The results showed that the processed polymeric materials acquired a substantial degree of ionisation without undergoing hydrolysis of the esterified groups. Furthermore, such changes improved the flow characteristics of the material and the solubility in aqueous media at pH > 5, while also maintaining the hydrophobicity degree of the polymeric surface.

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Synthesis of Hydrophilic Poly(butylene succinate-butylene dilinoleate) (PBS-DLS) Copolymers Containing Poly(ethylene glycol) (PEG) of Variable Molecular Weights

Polymers ◽

10.3390/polym13183177 ◽

2021 ◽

Vol 13 (18) ◽

pp. 3177

Author(s):

Moein Zarei ◽

Miroslawa El Fray

Keyword(s):

Molecular Weight ◽

Thermal Properties ◽

Ethylene Glycol ◽

Polymeric Materials ◽

Glycol Succinate ◽

Resonance Spectroscopy ◽

Scanning Calorimetry ◽

Water Contact ◽

Butylene Succinate ◽

Molecular Weights

Polymeric materials have numerous applications from the industrial to medical fields because of their vast controllable properties. In this study, we aimed to synthesize series of poly(butylene succinate-dilinoleic succinate-ethylene glycol succinate) (PBS-DLS-PEG) copolymers, by two-step polycondensation using a heterogeneous catalyst and a two-step process. PEG of different molecular weights, namely, 1000 g/mol and 6000 g/mol, was used in order to study its effect on the surface and thermal properties. The amount of the PBS hard segment in all copolymers was fixed at 70 wt%, while different ratios between the soft segments (DLS and PEG) were applied. The chemical structure of PBS-DLS-PEG was evaluated using Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. Gel permeation chromatography was used to determine the molecular weight and dispersity index. The results of structural analysis indicate the incorporation of PEG in the macrochain. The physical and thermal properties of the newly synthesized copolymers were also evaluated using water contact angle measurements, differential scanning calorimetry and dynamic thermomechanical analysis. It was found that increasing the amount of PEG of a higher molecular weight increased the surface wettability of the new materials while maintaining their thermal properties. Importantly, the two-step melt polycondensation allowed a direct fabrication of a polymeric filament with a well-controlled diameter directly from the reactor. The obtained results clearly show that the use of two-step polycondensation in the melt allows obtaining novel PBS-DLS-PEG copolymers and creates new opportunities for the controlled processing of these hydrophilic and thermally stable copolymers for 3D printing technology, which is increasingly used in medical techniques.

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Forensic Engineering of Advanced Polymeric Materials—Part VII: Degradation of Biopolymer Welded Joints

Polymers ◽

10.3390/polym12051167 ◽

2020 ◽

Vol 12 (5) ◽

pp. 1167

Author(s):

W. Sikorska ◽

M. Zięba ◽

M. Musioł ◽

M. Kowalczuk ◽

H. Janeczek ◽

...

Keyword(s):

Degradation Products ◽

Bond Cleavage ◽

Hydrolytic Degradation ◽

Welding Process ◽

Polymeric Materials ◽

Polymer Materials ◽

Scanning Calorimetry ◽

Forensic Engineering ◽

The Impact ◽

Welding Processes

Welding technology may be considered as a promising processing method for the formation of packaging products from biopolymers. However, the welding processes used can change the properties of the polymer materials, especially in the region of the weld. In this contribution, the impact of the welding process on the structure and properties of biopolymer welds and their ability to undergo hydrolytic degradation will be discussed. Samples for the study were made from polylactide (PLA) and poly(3-hydroxyalkanoate) (PHA) biopolymers which were welded using two methods: ultrasonic and heated tool welding. Differential scanning calorimetry (DSC) analysis showed slight changes in the thermal properties of the samples resulting from the processing and welding method used. The results of hydrolytic degradation indicated that welds of selected biopolymers started to degrade faster than unwelded parts of the samples. The structure of degradation products at the molecular level was confirmed using mass spectrometry. It was found that hydrolysis of the PLA and PHA welds occurs via the random ester bond cleavage and leads to the formation of PLA and PHA oligomers terminated by hydroxyl and carboxyl end groups, similarly to as previously observed for unwelded PLA and PHA-based materials.

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Effectiveness of Esterification Catalysts in the Synthesis of Poly(Ethylene Vanillate)

Catalysts ◽

10.3390/catal11070822 ◽

2021 ◽

Vol 11 (7) ◽

pp. 822

Author(s):

Eleftheria Xanthopoulou ◽

Alexandra Zamboulis ◽

Zoi Terzopoulou ◽

Margaritis Kostoglou ◽

Dimitrios N. Bikiaris ◽

...

Keyword(s):

Evolved Gas Analysis ◽

Group Analysis ◽

Polymeric Materials ◽

Gas Analysis ◽

Color Measurement ◽

Resonance Spectroscopy ◽

Antimony Trioxide ◽

Scanning Calorimetry ◽

Titanium Butoxide ◽

Poly Ethylene

Over the last few decades, bio-based polymers have attracted considerable attention from both academic and industrial fields regarding the minimization of the environmental impact arising from the excessive use of petrochemically-based polymeric materials. In this context, poly(ethylene vanillate) (PEV), an alipharomatic polyester prepared from 4-(2-hydroxyethoxy)-3-methoxybenzoic acid, a monomer originating from lignin-derived vanillic acid, has shown promising thermal and mechanical properties. Herein, the effects of three different catalysts, namely titanium butoxide (TBT), titanium isopropoxide (TIS), and antimony trioxide (Sb2O3), on the synthesis of PEV via a two-stage melt polycondensation method are investigated. The progress of the reaction is assessed using various complementary techniques, such as intrinsic viscosity measurement (IV), end group analysis (AV), nuclear magnetic resonance spectroscopy (NMR), Fourier-transformed infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). The thermal stability of the produced polyesters is studied by evolved gas analysis mass spectrometry (EGA-MS). Moreover, as the discoloration in polymers affects their applications, color measurement is performed here. Finally, theoretical kinetic studies are carried out to rationalize the experimental observations.

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On the Effectiveness of Oxygen Plasma and Alkali Surface Treatments to Modify the Properties of Polylactic Acid Scaffolds

Polymers ◽

10.3390/polym13101643 ◽

2021 ◽

Vol 13 (10) ◽

pp. 1643

Author(s):

Ricardo Donate ◽

María Elena Alemán-Domínguez ◽

Mario Monzón

Keyword(s):

Surface Properties ◽

Enzymatic Degradation ◽

Oxygen Plasma ◽

Physicochemical Characterization ◽

Surface Treatments ◽

Carboxyl Groups ◽

Scanning Calorimetry ◽

Water Contact ◽

Angle Measurements ◽

3D Printed

Surface modification of 3D-printed PLA structures is a major issue in terms of increasing the biofunctionality and expanding the tissue engineering applications of these parts. In this paper, different exposure times were used for low-pressure oxygen plasma applied to PLA 3D-printed scaffolds. Alkali surface treatments were also evaluated, aiming to compare the modifications introduced on the surface properties by each strategy. Surface-treated samples were characterized through the quantification of carboxyl groups, energy-dispersive X-ray spectroscopy, water contact angle measurements, and differential scanning calorimetry analysis. The change in the surface properties was studied over a two-week period. In addition, an enzymatic degradation analysis was carried out to evaluate the effect of the surface treatments on the degradation profile of the 3D structures. The physicochemical characterization results suggest different mechanism pathways for each type of treatment. Alkali-treated scaffolds showed a higher concentration of carboxyl groups on their surface, which enhanced the enzymatic degradation rate, but were also proven to be more aggressive towards 3D-printed structures. In contrast, the application of the plasma treatments led to an increased hydrophilicity of the PLA surface without affecting the bulk properties. However, the changes on the properties were less steady over time.

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Proof-of-Concept of Detection of Counterfeit Medicine through Polymeric Materials Analysis of Plastics Packaging

Polymers ◽

10.3390/polym13132185 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2185

Author(s):

Mohammad Salim ◽

Riyanto Teguh Widodo ◽

Mohamed Ibrahim Noordin

Keyword(s):

Polymeric Materials ◽

Proof Of Concept ◽

Scanning Calorimetry ◽

Counterfeit Drug ◽

Drug Products ◽

Counterfeit Medicines ◽

Counterfeit Medicine ◽

Counterfeit Pharmaceuticals ◽

Purge Gas ◽

Sample Set

The detection of counterfeit pharmaceuticals is always a major challenge, but the early detection of counterfeit medicine in a country will reduce the fatal risk among consumers. Technically, fast laboratory testing is vital to develop an effective surveillance and monitoring system of counterfeit medicines. This study proposed the combination of Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) and Differential Scanning Calorimetry (DSC) for the quick detection of counterfeit medicines, through the polymer analysis of blister packaging materials. A sample set containing three sets of original and counterfeit medicine was analyzed using ATR-FTIR and DSC, while the spectra from ATR-FTIR were employed as a fingerprint for the polymer characterization. Intending to analyze the polymeric material of each sample, DSC was set at a heating rate of 10 °C min−l and within a temperature range of 0- 400 °C, with nitrogen as a purge gas at a flow rate of 20 ml min−an. The ATR-FTIR spectra revealed the chemical characteristics of the plastic packaging of fake and original medicines. Further analysis of the counterfeit medicine’s packaging with DSC exhibited a distinct difference from the original due to the composition of polymers in the packaging material used. Overall, this study confirmed that the rapid analysis of polymeric materials through ATR-FTIR and comparing DSC thermograms of the plastic in their packaging effectively distinguished counterfeit drug products.

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Physicochemical properties and structural dynamics of organic–inorganic hybrid [NH3(CH2)3NH3]ZnX4 (X = Cl and Br) crystals

Scientific Reports ◽

10.1038/s41598-021-87940-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ae Ran Lim ◽

Sun Ha Kim ◽

Yong Lak Joo

Keyword(s):

Structural Dynamics ◽

Chemical Shifts ◽

Lattice Relaxation ◽

Magic Angle Spinning ◽

Spin Lattice Relaxation ◽

Resonance Spectroscopy ◽

Magic Angle ◽

Scanning Calorimetry ◽

Inorganic Hybrid ◽

Halogen Atoms

AbstractThe physical properties of the organic–inorganic hybrid crystals having the formula [NH3(CH2)3NH3]ZnX4 (X = Cl, Br) were investigated. The phase transition temperatures (TC; 268K for Cl and 272K for Br) of the two crystals bearing different halogen atoms in their skeletons were determined through differential scanning calorimetry. The thermodynamic properties of the two crystals were investigated through thermogravimetric analysis. The structural dynamics, particularly the role of the [NH3(CH2)3NH3] cation, were probed through 1H and 13C magic-angle spinning nuclear magnetic resonance spectroscopy as a function of temperature. The 1H and 13C NMR chemical shifts did not show any changes near TC. In addition, the 1H spin–lattice relaxation time (T1ρ) varied with temperature, whereas the 13C T1ρ values remained nearly constant at different temperatures. The T1ρ values of the atoms in [NH3(CH2)3NH3]ZnCl4 were higher than those in [NH3(CH2)3NH3]ZnBr4. The observed differences in the structural dynamics obtained from the chemical shifts and T1ρ values of the two compounds can be attributed to the differences in the bond lengths and halogen atoms. These findings can provide important insights or potential applications of these crystals.

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Synthesis and Characterization of N-Substituted Polyether-Block-Amide Copolymers

Materials ◽

10.3390/ma14040773 ◽

2021 ◽

Vol 14 (4) ◽

pp. 773

Author(s):

Jyun-Yan Ye ◽

Kuo-Fu Peng ◽

Yu-Ning Zhang ◽

Szu-Yuan Huang ◽

Mong Liang

Keyword(s):

Titanium Isopropoxide ◽

Decomposition Temperature ◽

Phenyl Isocyanate ◽

Cross Linking ◽

Resonance Spectroscopy ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

Degradation Temperature ◽

Melt Polycondensation ◽

Structural Regularity

A series of N-substituted polyether-block-amide (PEBA-X%) copolymers were prepared by melt polycondensation of nylon-6 prepolymer and polytetramethylene ether glycol at an elevated temperature using titanium isopropoxide as a catalyst. The structure, thermal properties, and crystallinity of PEBA-X% were investigated using nuclear magnetic resonance spectroscopy, Fourier-transform infrared spectroscopy, differential scanning calorimetry, wide angle X-ray diffraction, and thermogravimetric analysis. In general, the crystallinity, melting point, and thermal degradation temperature of PEBA-X% decreased as the incorporation of N-methyl functionalized groups increased, owing to the disruption caused to the structural regularity of the copolymer. However, in N-acetyl functionalized analogues, the crystallinity first dropped and then increased because of a new γ form arrangement that developed in the microstructure. After the cross-linking reaction of the N-methyl-substituted derivative, which has electron-donating characteristics, with poly(4,4′-methylenebis(phenyl isocyanate), the decomposition temperature of the resulting polymer significantly increased, whereas no such improvements could be observed in the case of the electro-withdrawing N-acetyl-substituted derivative, because of the incompleteness of its cross-linking reaction.

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Effect of DMPA and Molecular Weight of Polyethylene Glycol on Water-Soluble Polyurethane

Polymers ◽

10.3390/polym11121915 ◽

2019 ◽

Vol 11 (12) ◽

pp. 1915 ◽

Cited By ~ 2

Author(s):

Eyob Wondu ◽

Hyun Woo Oh ◽

Jooheon Kim

Keyword(s):

Molecular Weight ◽

Contact Angle ◽

Polyethylene Glycol ◽

Photoelectron Spectroscopy ◽

Water Solubility ◽

Soft Segment ◽

Water Soluble ◽

Size Exclusion ◽

Resonance Spectroscopy ◽

Scanning Calorimetry

In this study water-soluble polyurethane (WSPU) was synthesized from isophorone diisocyanate (IPDI), and polyethylene glycol (PEG), 2-bis(hydroxymethyl) propionic acid or dimethylolpropionic acid (DMPA), butane-1,4-diol (BD), and triethylamine (TEA) using an acetone process. The water solubility was investigated by solubilizing the polymer in water and measuring the contact angle and the results indicated that water solubility and contact angle tendency were increased as the molecular weight of the soft segment decreased, the amount of emulsifier was increased, and soft segment to hard segment ratio was lower. The contact angle of samples without emulsifier was greater than 87°, while that of with emulsifier was less than 67°, indicating a shift from highly hydrophobic to hydrophilic. The WSPU was also analyzed using Fourier transform infrared spectroscopy (FT-IR) to identify the absorption of functional groups and further checked by X-ray photoelectron spectroscopy (XPS). The molecular weight of WSPU was measured using size-exclusion chromatography (SEC). The structure of the WSPU was confirmed by nuclear magnetic resonance spectroscopy (NMR). The thermal properties of WSPU were analyzed using thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC).

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Formation of flavorant–propylene Glycol Adducts With Novel Toxicological Properties in Chemically Unstable E-Cigarette Liquids

Nicotine & Tobacco Research ◽

10.1093/ntr/nty192 ◽

2018 ◽

Vol 21 (9) ◽

pp. 1248-1258 ◽

Cited By ~ 41

Author(s):

Hanno C Erythropel ◽

Sairam V Jabba ◽

Tamara M DeWinter ◽

Melissa Mendizabal ◽

Paul T Anastas ◽

...

Keyword(s):

Propylene Glycol ◽

Electronic Cigarettes ◽

Aqueous Media ◽

Chemical Species ◽

Resonance Spectroscopy ◽

Reaction Products ◽

Chemical Systems ◽

Toxicological Effects ◽

Wide Range ◽

Irritant Receptors

Abstract Introduction “Vaping” electronic cigarettes (e-cigarettes) is increasingly popular with youth, driven by the wide range of available flavors, often created using flavor aldehydes. The objective of this study was to examine whether flavor aldehydes remain stable in e-cigarette liquids or whether they undergo chemical reactions, forming novel chemical species that may cause harm to the user. Methods Gas chromatography was used to determine concentrations of flavor aldehydes and reaction products in e-liquids and vapor generated from a commercial e-cigarette. Stability of the detected reaction products in aqueous media was monitored by ultraviolet spectroscopy and nuclear magnetic resonance spectroscopy, and their effects on irritant receptors determined by fluorescent calcium imaging in HEK-293T cells. Results Flavor aldehydes including benzaldehyde, cinnamaldehyde, citral, ethylvanillin, and vanillin rapidly reacted with the e-liquid solvent propylene glycol (PG) after mixing, and upward of 40% of flavor aldehyde content was converted to flavor aldehyde PG acetals, which were also detected in commercial e-liquids. Vaping experiments showed carryover rates of 50%–80% of acetals to e-cigarette vapor. Acetals remained stable in physiological aqueous solution, with half-lives above 36 hours, suggesting they persist when inhaled by the user. Acetals activated aldehyde-sensitive TRPA1 irritant receptors and aldehyde-insensitive TRPV1 irritant receptors. Conclusions E-liquids are potentially reactive chemical systems in which new compounds can form after mixing of constituents and during storage, as demonstrated here for flavor aldehyde PG acetals, with unexpected toxicological effects. For regulatory purposes, a rigorous process is advised to monitor the potentially changing composition of e-liquids and e-vapors over time, to identify possible health hazards. Implications This study demonstrates that e-cigarette liquids can be chemically unstable, with reactions occurring between flavorant and solvent components immediately after mixing at room temperature. The resulting compounds have toxicological properties that differ from either the flavorants or solvent components. These findings suggest that the reporting of manufacturing ingredients of e-liquids is insufficient for a safety assessment. The establishment of an analytical workflow to detect newly formed compounds in e-liquids and their potential toxicological effects is imperative for regulatory risk analysis.

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Synthesis, Characterization and Application of Multi-Generations Hyperbranched Polyurethane Based on Isophorone Diisocyanate

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.554-556.126 ◽

2012 ◽

Vol 554-556 ◽

pp. 126-129 ◽

Cited By ~ 3

Author(s):

Shun Yin ◽

Ning Sun ◽

Chun Yun Feng ◽

Zhi Mou Wu ◽

Zhao Hua Xu ◽

...

Keyword(s):

Differential Scanning Calorimetry ◽

Raw Materials ◽

Degradation Mechanism ◽

Resonance Spectroscopy ◽

Gravimetric Analysis ◽

Thermal Gravimetric ◽

Isophorone Diisocyanate ◽

Scanning Calorimetry ◽

Degradation Temperature ◽

Hyperbranched Polyurethane

A series of different generation hyperbranched polyurethane(HBPU) was synthesized based on the raw materials of isophorone diisocyanate(IPDI) and diethanolamine(DEOA). Their structure, thermal degradation mechanism and glass transition temperature(Tg) were characterized by fourier transform infrared spectroscopy(FTIR), nuclear magnetic resonance spectroscopy(NMR), thermal gravimetric analysis(TGA) and differential scanning calorimetry(DSC). The results showed that: the yield of each generation HBPU was up to 90%, different generation HBPU had almost the same initial degradation temperature(about at 200°C) and they all had two decomposition platforms; with the increase of generation, Tg increased from 107.2°C to 132.1°C. The gloss and hardness of the HBPU coatings were significantly improved.

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