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The main object of this report is to review and summarize the current state of the scientific literature relating to physico-chemical ageing of ethylene–norbornene copolymers (ENCs). These processes occur through different means such as photodegradation under the effect of ultraviolet radiation, temperature and ionizing radiation (under air or oxyg...
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... The use of mechanical forces can be traced back to the use of friction to create fire, and since then it has been used in extractive metallurgy, crystal engineering, materials engineering, the coal industry, the construction industry, agriculture, pharmaceuticals, and waste treatment. The technology covers many important reactions such as faster decomposition and synthesis [15], grafting [16], and polycrystalline transformations [17]. Mechanical forces have potential applications in pollution remediation and waste management for fly ash, coal gangue, and weathered coal, etc. [18]. ...
Humic acid (HA) is rich in functional groups with high activity, which can effectively improve the soil environment. The large reserves of weathered coal in China provide sufficient raw material guarantee for HA extraction and utilization. At present, the activation side of weathered coal is still the main technical difficulty that restricts HA extraction. In this study, the weathered coal from Inner Mongolia was used as the raw material, and the mechanical energy was used to activate the weathered coal through a planetary ball mill, which improved the extraction rate of HA and optimized the molecular structure and composition of HA. The effects of four parameters, namely, ball material ratio, ball milling time, ball milling speed, and ball size, on the free HA content of weathered coal were investigated, the HA was extracted by alkaline extraction method, and the activated weathered coal and the extracted HA were characterized. The results showed that a ball material ratio of 9:1, a ball milling speed of 200 r/min, a ball milling time of 200 min, a milling ball size of Ф5:Ф10:Ф15 = 48:42:45 and 56:42:37 are the optimal parameters for the mechanical energy activation, and the HA extraction rate of activated weathered coal under these conditions reached 82.3%, which was 15% higher than that of the unactivated one. Moreover, the aroma of the ball-milled weathered coal increased, the content of oxygenated functional groups increased, and the molecular weight and aroma of HA increased. This provides scientific theoretical guidance for the preparation of HA with high aromaticity and large molecular weight from weathered coal.
... Cyclic olefin polymer (COP) and copolymer (COC) are engineering thermoplastics derived from the ring-shaped norbornene molecule, which can be seen in Figure 1. These are amorphous and inexpensive polyolefins with interesting properties including a high glass transition temperature (T g : 80-180 • C), good mechanical properties, low moisture absorption, low density, excellent strength and hardness, little shrinkage, good electrical properties, low thermal conductivity, very good melt processability, good biocompatibility (i.e., very good blood compatibility), and high chemical resistance to acids, alkalis, and polar organic solvents [14]. COP is closely related to cyclic olefin copolymer (COC) with some differences including the synthesis process, T g value, moisture absorption, and cost, among others. ...
... Cyclic olefin polymer (COP) and copolymer (COC) are engineering thermoplastics derived from the ring-shaped norbornene molecule, which can be seen in Figure 1. These are amorphous and inexpensive polyolefins with interesting properties including a high glass transition temperature (Tg: 80-180 °C), good mechanical properties, low moisture absorption, low density, excellent strength and hardness, little shrinkage, good electrical properties, low thermal conductivity, very good melt processability, good biocompatibility (i.e., very good blood compatibility), and high chemical resistance to acids, alkalis, and polar organic solvents [14]. COP is closely related to cyclic olefin copolymer (COC) with some differences including the synthesis process, Tg value, moisture absorption, and cost, among others. ...
... In our previous studies, the first porous COP films were designed and used as membranes for desalination and CO2 capture [16,17]. [14]. ...
For the first time, a systematic study to investigate the electrospinnability of cyclic olefin polymer (COP) was performed. Different solvents and mixtures were tested together with different electrospinning parameters and post-treatment types to prepare bead-free fibers without defects. These were successfully obtained using a chloroform/chlorobenzene (40/60 wt.%) solvent mixture with a 15 wt.% COP polymer, a 1 mL/h polymer solution flow rate, a 15 cm distance between the needle and collector, and a 12 kV electric voltage. COP fibers were in the micron range and the hot-press post-treatment (5 MPa, 5 min and 120 °C) induced an integrated fibrous structure along with more junctions between fibers, reducing the mean and maximum inter-fiber space. When the temperature of the press post-treatment was increased (from 25 °C to 120 °C), better strength and less elongation at break of COP fibers were achieved. However, when applying a temperature above the COP glass temperature (Tg = 138 °C) the fibers coalesced, showing a mechanical behavior similar to a plastic film and a low elongation at break with a high strength. The addition of a high dielectric constant non-solvent, N,N-dimethylacetamide (DMAc), resulted in a considerable reduction in the COP fiber diameter. Based on the cloud point approach, it was found that the use of DMAc and the solvent chloroform or chlorobenzene improved the electrospinnability of COP polymer solution.
... When further increasing the irradiation time, the breakdown strengths decrease, which might be related to the possible degradation of COC-6017S-04 films by excessive UV irradiation. 26,27,29,40 The typical unipolar electric displacement-electric field (D-E) of the pristine film and irradiated COC-6017S-04 films was measured, as displayed in Fig. 3(c) and Fig. S6 (ESI †). For each sample, the D-E loops with different maximum electric fields were measured with increasing the maximum electric fields by a step of 10 MV m À1 until the breakdown occurred. ...
Polymer dielectrics with high operation temperature (∼150 °C) and excellent capacitive energy storage performance are vital for electric power systems and advanced electronic devices. Here, a very convenient and competitive strategy by preparing ultraviolet-irradiated cyclic olefin copolymer films is demonstrated to be effective in improving the energy storage performance at high temperatures. Compared with the unirradiated film, irradiated films exhibit a higher dielectric constant, higher breakdown strength and stronger mechanical properties as a result of the emergence of the carbonyl group and cross-linking network. Consequently, with a high efficiency above 95%, a superior discharged energy density of ∼3.34 J cm-3 is achieved at 150 °C, surpassing the current dielectric polymers and polymer nanocomposites. In particular, the energy storage performance remains highly reliable over 20 000 cycles under actual operating conditions (200 MV m-1 at 150 °C) in hybrid electric vehicles. This research offers a valuable pathway to build high-energy-density polymer-based capacitor devices working under harsh environments.
... Their characteristic profiles can be varied over a wide interval by adjusting the chemical composition during synthesis; for instance, their glass transition temperature (Tg) significantly increases as cyclic olefin content is raised [15][16][17][18]. Nevertheless, some efforts have been made toward studying their thermal stability under both oxidative and inert conditions [17,19], in order to find out whether their use is beneficial for high-temperature applications, such as in capacitor dielectrics, as well as to reduce energy consumption in potential pyrolytic recovery processes. ...
... Their characteristic profiles can be varied over a wide interval by adjusting the chemical composition during synthesis; for instance, their glass transition temperature (T g ) significantly increases as cyclic olefin content is raised [15][16][17][18]. Nevertheless, some efforts have been made toward studying their thermal stability under both oxidative and inert conditions [17,19], in order to find out whether their use is beneficial for high-temperature applications, such as in capacitor dielectrics, as well as to reduce energy consumption in potential pyrolytic recovery processes. ...
Different circular strategies attempt to increase the energy efficiency or reduce the accumulation of plastic in landfills through the development of circular polymers. Chemical recycling is essential to recover the initial monomers from plastic residues for obtaining new goods showing the same properties as those using virgin monomers from the initial feedstocks. This work addresses the preparation of poly(ethylene-co-norbornene) copolymers for a promising generation of materials for energy applications that could be treated by chemical recycling. The thermal and thermo-oxidative stability for these copolymers with norbornene is higher than for the neat PE, while their degradation exhibits an activation energy lower than that observed in PE, pointing out that chemical recycling would require a lower energy consumption.
... In order to overcome these drawbacks, polar vinyl monomers and polar norbornene derivatives were always employed as comonomer during the polymerization processes to prepare functionalized PNBs. [6][7][8][9][10][11][12][13] Even if the polymers bear about 1 mol% of polar groups, their application performance could be improved obviously. ...
... As similar to the NBE/n-BMA copolymers, the obtained NBE/n-DBI could not well dissolve in common solvents under room temperatures. Therefore, the 13 C NMR analysis could not be well carried out. Additionally, the resultant copolymers showed high T g s as 289-314 C, which was slightly lower than that of PNB. ...
Four asymmetric α‐diimine dibromide nickel (II) complexes bearing both 2,6‐diisopropyl phenyl and substituted triphenyl {[(C3H7)2C6H3NC(C10H6)CN(R2C6H3)2C6H3]NiBr2, R = CH3, Catal.1; CF3, Catal.2; OCH3, Catal.3; C6H5, Catal.4} were synthesized and characterized. In the presence of B(C6F5)3, these newly synthesized nickel complexes showed high activities toward norbornene (NBE) homo‐polymerization (0.84‐4.88×105 gpolymer/molNi‧h) under elevated temperatures, yielding high molecular weight polymers (106.5‐657.9kDa). These Ni/B catalytic systems also efficiently promoted the copolymerization of NBE with n‐butyl methacrylate (n‐BMA) and di(n‐butyl) itaconate (n‐DBI) under 70 °C, respectively, affording copolymers with high molecular weight (n‐BMA: 95.0‐235 kDa; n‐DBI:35.4‐52.5 kDa) and moderate polar monomer incorporations (n‐BMA:1.2‐6.4 mol%; n‐DBI:0.8‐2.8 mol%). The copolymers with polar groups showed improved solubilities. The unimodal molecular weight distribution of the resultant polymers implied the single site catalytic behavior of these nickel catalysts towards NBE (co)polymerization. In addition, both the obtained PNB and the copolymers showed high glass transition temperature (289‐345 °C) and excellent thermal stability.
... In addition, COP shows outstanding properties including high heat resistance, low specific gravity, viscosity and thermal conductivity coefficient (0.12-0.15 W/m. K), and very good melt processability [14,15]. ...
Porous flat sheet membranes were prepared with a commercial grade of cyclic olefin polymer (COP) for CO2 capture using membrane contactor (MC). The membranes were prepared via non-solvent induced phase separation technique using different types of additives, namely, polyvinylpyrrolidone (PVP), polyethylene glycol (PEG400) and sorbitan monooleate (Span 80), and coagulants (acetone and 70/30 wt% acetone/water mixture) were investigated. The prepared membranes were characterized in terms of the thickness (70 - 85 µm), porosity (50 - 80%), mean pore size (158 - 265 nm), bubble pore size (~ 0.6 - 12 µm), liquid entry pressure (1.67- 4.55 bar), water contact angle (~ 94º - 111º), monoethanolamine (MEA) contact angle (~ 67º - 73º) and mechanical properties (tensile strength: 4.53 – 5.15 MPa, elongation at break: 4 – 8% and Young´s modulus: 190 – 232 MPa). The thermodynamic study of COP membranes proved that a fast phase inversion of the proposed system resulted in a more porous structure. The addition of PEG400 and Span 80 caused delayed demixing and influenced the morphological structure and MC performance. The structural and topographical characteristics of the membranes were also studied. The CO2 absorption test performed at 27 ºC showed that the maximum CO2 absorption flux was around 16×10-5 mol/m².s using 1 M MEA aqueous solution as absorbent with fixed liquid and gas flow rates at 150 L/h and 8.4 L/h, respectively. It was found that the considered additives enhanced the MC performance and affected the CO2 absorption flux.
... Due to its good dielectric resistance over a wide temper-ature range, EN can be used to replace other polymers, for example polypropylene in thin film capacitors. There are numerous studies in the literature describing the synthesis or modification of different grades of EN copolymers, but only a few have investigated the impact of UV aging on these materials [40,41]. It is known that long-term ultraviolet radiation causes photooxidative degradation, which results in the breakage of polymer chains, producing radicals and reducing the molecular weight [42]. ...
... Due to its good dielectric resistance over a wide temperature range, EN can be used to replace other polymers, for example polypropylene in thin film capacitors. There are numerous studies in the literature describing the synthesis or modification of different grades of EN copolymers, but only a few have investigated the impact of UV aging on these materials [40,41]. It is known that long-term ultraviolet radiation causes photooxidative degradation, which results in the breakage of polymer chains, producing radicals and reducing the molecular weight [42]. ...
Multicolor ethylene-norbornene (EN) composites filled with three different spinel pigments (Cobalt Green-PG50, Zinc Iron Yellow-PY 119, Praseodym Yellow-PY159) were prepared by melt mixing and characterized in terms of their stability under destructive environmental conditions. The EN films were subjected to accelerated aging by ultraviolet (UV) photooxidation for 300 h, 600 h, or 900 h. The mechanical performance of the EN composites was investigated in static and dynamic mechanical tests. The morphologies of the EN samples and their color changes during the aging process were evaluated by scanning electron microscopy (SEM) and spectrophotometric measurements. Fourier transform infrared (FTIR) spectroscopy was applied to determine the amount of carbonyl groups resulting from surface oxidation at different aging times. The effects of the spinel pigments on the thermal stability and combustion properties of the multicolor polymer composites were also assessed, and compared with a sample containing the organic Pigment Yellow 139 (PY139). The results show that the color changes (ΔE) in the spinel pigments were minor in comparison to those in the organic pigment (PY139) and the reference film. The Zinc Yellow (PY119) pigment was the most effective stabilizer of EN copolymer. Moreover, the spinel pigments had a positive effect on the flame retardancy of the EN composites. Microcombustion tests (MCC) showed that the incorporation of both the spinels and the organic pigment PY139 into the EN matrix reduced the heat release rate (HRR) and total heat release (THR) parameters.
... Thermal properties such as glass transition temperature depend on their norbornene and ethylene monomer proportion [22]. COC have applications in drug packaging, medical and diagnostic devices like biosensors [23], microfluidic devices and biochips, nucleic acid immobilization and purification, immunoassays [24], and in articular cartilage creation [25]. ...
Cyclic olefinic copolymer Blends Tensile and compressive strength Crystallinity Cytotoxicity Bone tissue engineering a b s t r a c t Poly (L-lacticacid) (PLLA) is an FDA approved material for bone tissue engineering but its inherent brittleness and low melting ability are major challenges for its large-scale commercial applications. This challenge can be overcome by making its blends. This study reports blends of PLLA with a relatively new class of polymer i.e. cyclic olefinic copolymer and their misci-bility, thermal behavior, morphology, crystallinity, degradability, and excellent biocompati-bility is evaluated. Blends were prepared by taking 5e30 weight percent COC with PLLA matrix using solvent casting method. Scanning electron microscopy (SEM) images revealed that PLLA/ COC form miscible blends up to 5e20 wt% of COC. FTIR, XRD, and differential scanning calo-rimetry (DSC) data showed that addition of COC to PLLA resulted in decrease in crystallinity along with formation of new a 0-crystalline phase which coexists with inherent a-phase of PLLA in the blends. The transformation of a 0-form is due to the presence of Van der Waals forces of interactions of the polymer chain moieties between PLLA and COC. Interestingly, PLLA/COC blends exhibited superior mechanical properties in relation to the pure PLLA. Compressive modulus values for PLLA/COC 10wt% increased 117% as compared to pure PLLA. PLLA/COC blends at 10 wt% have maximum ultimate tensile strength, modulus, and toughness~123%, 67.8% and, 18.87% respectively. PLLA/COC blends showed increased swelling and degradation results as compared to PLLA. PLLA/COC blends exhibited excellent cytocompatibility over PLLA with preosteoblast (MC3T3-E1) and bone marrow stem cells (BMSc) cell lines suggesting possible candidate for Bone Tissue Engineering.
... Changes in the chemical composition and physical properties of the interface and structure of COC may have great consequences in their global biocompatible characteristics [5]. Aging process under various experimental conditions are detailed by Lago et al., [6], where authors show that physico-chemical aging of COC may occur through different mechanism like photodegradation after ultraviolet radiations, temperature and ionizing radiation, leading to high-mobile-degradation-compounds' formation with low molecular weight and/or high polarity, due to chains scissions. Crosslinking can also occur, inducing mechanical properties modifications. ...
... The IR analysis confirmed this hypothesis with no observed differences except in the hypochlorite incubation with a slight modification in carbonyls groups' absorption, indicating a global surface oxidation of COC in this exaggerated incubation condition. It is also known that thermo-oxidation aging of COC induced changes in IR spectrum but only for temperature above 250°C which is far higher than the present tested physiological conditions of 37°C [6]. Polymer chains modification like chain scissions or oxidation, which could have explained this surface changes phenomenon, is therefore not expected under the present conditions. ...
... Polymer oxidation is a complex process involving many factors including temperature, shear rate, presence of oxidation catalysts, compounding formulation design, etc. [21]. It has already been shown that the thermo-oxidative stability of COC is influenced by antioxidant presence with a protective effect and that norbornene content influences photodegradation [6]. In the present study, antioxidant presence was associated with a protective effect against THP-1 attacks on COC surface. ...
We study the effect of simulated biological aging on the properties of cyclic olefin copolymers and particularly their biocompatibility. Already reported as biocompatible polymers according to ISO/EN 10993 guidelines, COC are good candidates for medical devices. The influence of two major additives (antioxidants and lubricants) was investigated and comparison with non-aging COC was done. Four in vitro simulated biological conditions were tested: 2 extreme pH (1 and 9) to simulate digestive tract environment; THP-1-derived macrophages contact and pro-oxidant medium with hypochlorite solution simulating the oxidative attack during the foreign body reaction. After one month of incubation with the different media at 37 °C, surface topography was studied by atomic force microscopy (AFM) and IR spectroscopy. Extracts of incubated media were also analysed in chromatography to investigate potential degradation products. Cytotoxicity (MTT and LDH) of the materials was evaluated using cell culture methods with L929 fibroblasts. Oxidative stress (ROS and SOD analysis) and two inflammatory biomarkers (Il-6 and TNF-α secretion) were explored on THP-1-derived macrophages in direct contact with aged COC. Surface topography of COC was modified by aging conditions with an influence of antioxidant presence and under some conditions. HPLC analysis realized on freeze-dried solutions issued from the different incubations showed the presence of traces of low molecular weight compounds issued from polyphenolic antioxidant and from COC degradation. GC–MS analysis carried out directly on the different incubated COC, showed no detectable leachable molecules. No cytotoxicity has been observed with the different aged COC. However, results show that the pH environment had an influence on the cytotoxicity tests with a protecting effect of antioxidant presence; and pro-oxidant incubating conditions decreased cellular viability on COC. pH 1 and pH 9 conditions also induced an increase of ROS production which was partially reduced for COC containing an antioxidant or a lubricant. Il-6 production was globally more important for aged COC compared with basal condition and particularly for oxidative simulated environment. Those results indicate that physiological factors like pH or oxidant conditions have an impact on surface topography and on COC interaction with the biological environment but without compromising their biocompatibility. Antioxidant or lubricant presence could modulate these variations pointing out the necessity of a thoroughly investigation for biocompatibility assessment of COC as a component of implantable devices. COCs show a good biocompatibility even after accelerated aging under extreme biological conditions.
... Cyclic Olefin Copolymers (COC) form a class of thermoplastic polymers that can be synthesized by vinyl polymerization mechanism using homogenous metallocene catalysts, as firstly described in the late 1950s [1][2][3][4][5][6][7][8][9][10][11][12]. Among several cyclic olefin copolymers, Ethylene-Norbornene Copolymers (ENCs) are one of the most commercialized because of their advantageous characteristics including high transparency, glass-like texture, low moisture uptake, very high heat resistance, good chemical resistance and variable glass transition temperatures [13][14][15][16][17][18]. ...
... A large number of publications, dealing with the synthesis of COC have been published but only few papers deal with the effect of ionizing radiations on ENCs. For that reason, we recently published a review on the physico-chemical ageing of ENCs due to thermal oxidation, UV and ionizing radiation [1]. Ionizing sterilization by gamma or electron beam radiation is gaining popularity in medical devices and packaging industry, because of its reliability, convenience and cost saving when compared with other sterilization techniques such as dry heat, steam or ethylene oxide [32][33][34][35]. ...
... In this study, we used a tripled detection system. The DRI is a concentration detector whose signal follows equation (1). In order to overcome the limitations of conventional SEC, we used DP and LS detectors whose corresponding equations are (2) and (3) respectively. ...
Ethylene Norbornene Copolymers (ENCs) belong to the Cyclic Olefin Copolymers (COC) family and are used in numerous industrial fields. The goal of this paper is to compare the behavior under electron beam radiation of three grades of ENCs. Several radiation doses have been tested: 25 kGy to simulate sterilization dose and higher doses (75 and 150 kGy) to emphasize the electron beam effect on polymer ageing.
By using Triple Detection (Refractometer/Laser Scattering/Viscometer) Size-Exclusion Chromatography, we wanted to study more accurately the evolution of ENCs under radiation than the previous studies available. Thanks to Triple detection, molecular weights were calculated without being dependent of calibration standards, branching was evidenced as the major effect of electron beams on those materials over a dose of 25 kGy, and long chain branching and branching chains frequencies were also calculated.
This study focuses on the effect of additive concentration and norbornene (NB) content and a trend has merged: for a same NB content, the higher the phenolic antioxidant concentration, the less crosslinked was the copolymer with the dose. By increasing NB content, radiation effects were minimized.
