Copolymerization Of Norbornene Research Articles

Efficient synthesis of the cyclo-olefin copolymers at high temperature and pressure in a homogeneous mini-tubular reactor

Ethylene-norbornene copolymer (ENC) is one of the most representative cyclo-olefin copolymer (COC). Both the amorphous and semi-crystalline ENCs were efficiently synthesized by the homogeneous solution copolymerization of ethylene (E) and norbornene (NB) using rac-Et(Ind)2ZrCl2/triisobutylaluminium/(Ph3C)B(C6F5)4 ternary catalyst system in a visualized mini-tubular reactor under high temperature (90–130 °C) and given pressure (24 bar). An ultra-high activity of 7.6 × 108 g/(molZr h), as well as considerable efficiency of 14.1 kgENC/gZr was achieved in time of only 30 s at E/NB molar ratio of 3:1. Moreover, a quench-labeling method using 2-thiophenecarbonyl chloride (TPCC) was adopted to calculate the high proportion of active center [C*]/[Zr]. The novel strategy was proposed for preparation of the block semi-crystalline ENC elastomers with excellent tensile performance and high transparency via reversible chain transfer based on spatiotemporal concentration distribution in a mini-tubular reactor.

New Catalyst Systems for the Polymerization of Norbornene and Its Derivatives Based on Cationic Palladium Cyclopentadienyl Complexes

The catalytic properties of systems based on [Pd(Cp)(L)n]m[BF₄]m (where Cp = η5-C5H5; n = 2, m = 1: L = tris(orthomethoxyphenyl)phosphine, triphenylphosphine, tris(2-furyl)phosphine (TFP), n = 1, m = 1: L = 1,1'-bis(diphenylphosphino)ferrocene, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,5-bis(diphenylphosphino)pentane; n = 1, m = 2 or 3: L = 1,6-bis(diphenylphosphino)hexane) in the addition homoand copolymerization of norbornene (NB) and its derivatives have been studied. These complexes can be activated with the Lewis-acids (BF₃ ∙ OEt2 or AlCl3). The productivity of the [Pd(Cp)(PPh3)2][BF₄]/BF₃ ∙ OEt2 catalyst system in the polymerization of norbornene is up to 188800 molNB molPd⁻¹. The homopolymerization of 5-methoxycarbonylnorbornene and copolymerization of NB with 5-methoxycarbonylnorbornene or 5-phenylnorbornene were studied in the presence of BF₃ ∙ OEt2 and [Pd(Cp)(L)2][BF₄] (L = PPh3 or TFP). A hypothesis for the catalyst’s formation via the intramolecular rearrangement of the η5-Cp ligand into the η1-Cp form upon interaction with a Lewis acid is suggested. The structure of the [Pd(Cp)(TFP)2]BF₄ (I) was determined by X-ray diffraction. In the crystal structure of I, the palladium coordination sphere is characterized by a slight distortion of the square planar geometry of the central atom, and the cyclopentadiyl fragment is in an eclipsed conformation. Based on the XRD data, the steric hindrance of the TFP ligand was estimated (the cone angle is 149°).

Nickel‐ and Palladium‐Catalyzed Copolymerizations of Norbornene with Polar α‐Olefins

AbstractRecent progress regarding the copolymerization of norbornene with various polar α‐olefins catalyzed by nickel and palladium catalysts is reviewed here with special attention paid to the diverse catalyst frameworks, polar monomer scopes as well as polymer microstructures. Both the influences of steric effect and electron property of ligand substituents and the type of polar monomers on the catalytic behaviors (activity, stability, polarity tolerance, etc.) and the polymer microstructures (molecular weight and distribution, comonomer contents, etc.) have been summarized. The introduction of noncyclic‐olefins, such as polar vinyl monomers, polar higher α‐olefins, and polar styrenes, into rigid cyclic‐based polynorbornene chain resulted in significant modifications on the polarity, compatibility, thermostability, processibility, transparency, and many other properties of the material, which has also been discussed in the review. The contents of this review have been classified according to the type of polar monomers involved in the norbornene copolymerization, and each section included nickel and palladium catalysts bearing different ligand structures, which will be meaningful for the development of new types of catalysts and new families of norbornene‐based cyclic olefin copolymer materials in the future.

Copolymerization of norbornene with 1-hexene catalyzed by sulfur-containing Schiff base titanium complex and density functional theory analysis

Sulfur-containing salicylaldimine ligand and corresponding titanium complex were synthesized and characterized this work, indicating structural conformity with the design. By using diethylaluminum chloride (EADC) as a cocatalyst, the titanium complex exhibited high activity (∼106 g·mol−1·h−1) in the copolymerization of norbornene (NB) and 1-hexene (1-C6), producing oligomer with a molecular weight of approximately 500. The catalytic copolymerization results were interpreted by combining experimental analysis and density functional theory (DFT). The results indicated that the insertion of norbornene and 1-hexene into Ti catalysts was thermodynamically feasible. Although the reaction barrier for norbornene monomer insertion into the metal active center was lower than that of 1-hexene, the strong steric hindrance between NBE monomer and NBE units in the oligomer chain hindered continuous NBE insertion. By comparing the reaction rates in equimolar systems, the initial insertion step of 1-hexene monomer into the Ti-Et structure was found to be much easier than norbornene insertion, resulting in a lower quantity of norbornene groups in the copolymerization product than 1-hexene groups.

Vinyl-addition copolymerization of norbornene and 1-octene catalyzed by a non-bridged half-titanocene with a tetrazole-phenoxy ligand

A catalyst system comprising Cp*TiCl2(OPhTz) (Cp* = C5Me5, OPhTz = tetrazole-mono-ortho-substituted phenoxy anion), iBu3Al, and [Ph3C][B(C6F5)4] is employed in the vinyl-addition copolymerization of norbornene (NB) and 1-octene (OT) to understand the catalytic effects of the N-donor tetrazole substituent. Copolymerization is accompanied by significant β-hydride elimination, producing poly(norbornene-co-1-octene) (P(NB-co-OT)) with low yield and molecular weight. Although the incorporation of OT into the copolymer is less than expected, competitive incorporation of the two monomers is observed. Increasing the mole fraction of OT in the feed reduces both the yield and molecular weight of the copolymer. Spectroscopic analysis reveals that the catalyst system yields P(NB-co-OT)s that are terminated prior to complete monomer conversion, along with non-isolated cooligomers and OT-derived isomers. The cationic titanium(IV) center stabilized by the N-donor tetrazole substituent facilitates the highly regioselective 2,1-insertion of OT. This slows subsequent monomer insertion, thereby promoting β-hydride elimination.

Norbornene Copolymerization with Polar Monomers Catalyzed by Palladium Catalysts Containing Imidazolidin-2-imine/Guanidine Ligands.

The development of a palladium catalyst that has enhanced catalytic performance, such as low aluminum cocatalyst loading, good copolymerization ability, high molecular weight, and excellent solubility of the (co)polymers, is still a challenge in norbornene copolymerizations. Here, a series of PdCl2 and PdMeCl complexes containing differently substituted anilines and imidazolidin-2-imine/guanidine ligands was successfully synthesized and characterized. X-ray diffraction analysis results revealed that these Pd complexes adopted an almost square-planar geometry, and the six-membered chelate ring showed structural distinctions as compared to traditional N^N-based α-diimine and β-diimine Pd complexes. These Pd complexes were activated by EtAlCl2 and then exhibited moderate activity (104-105 g mol-1 h-1) and good thermal stability (up to 90 °C) for norbornene polymerization to produce high-molecular-weight PNBs (Mn up to 96.4 kg mol-1) with narrow polydispersities (PDI as low as 1.39). These Pd complexes also exhibited good polar group tolerance in the copolymerization of norbornene with methyl 5-norbornene-2-carboxylate and methyl 10-undecenoate, in which the activity was achieved up to 7.04 × 104 g mol-1 h-1. It furnished polar functionalized norbornene-based copolymers with high molecular weight (Mn up to 63.1 kg mol-1), narrow PDI, reasonable polar monomer incorporation, and good solubility. These Pd catalysts exhibited an enhanced copolymerization ability to produce PNB or NB-based copolymers, representing significant progress in this field.

Ni(II) and Pd(II) complexes bearing novel chiral bis(β-ketoamino) ligand and their catalytic activity toward copolymerization of norbornene and polar norbornene derivatives

A series of novel Ni(II) and Pd(II) complexes bearing chiral bis(β-ketoamino) ligand were synthesized and characterized. The Ni(II) and Pd(II) complexes exhibited high activities for norbornene homopolymerization with only B(C6F5)3 as cocatalyst, for Ni(II) complex even up to 1.38 ×106 gpolymer/molNi·h. All the complexes had good thermal stability. Most importantly, the complexes also displayed high activities of 105 gpolymer/molmetal·h toward the copolymerization of norbornene and 5-norbornene-2-yl acetate with high molecular weights and tunable norbornene and 5-norbornene-2-yl acetate content. The copolymerization activity, molecular weight, and norbornene and 5-norbornene-2-yl acetate feed ratio of the Ni complex were higher than those of the Pd complex.

Exploring the influence of rigid carbocycles on terpenoid copolymer properties

AbstractSynthesizing soft polymers with uncommon architectural elements is critical for enhancing our understanding of fundamental structure–property relationships in macromolecules. Terpenoid materials are interesting candidates for addressing this grand challenge, as their constituent monomers can exhibit a diverse array of structural and functional groups. Moreover, these biologically‐derived materials can potentially expand the sphere of knowledge surrounding trends in related petrochemically‐derived polymers. For example, vinyl‐addition copolymers of norbornene and acyclic olefins can exhibit predictable properties (e.g., linear changes in Tg as a function of composition). Due to synthetic limitations, however, it is not well understood if other rigid carbocycles engender similar behavior in a range of copolymers. As numerous terpene scaffolds display rigid motifs (such as pinane systems), terpenoid polymers are uniquely positioned to address this deficiency. Here, we report the synthesis and characterization of terpenoid copolymers (both statistical and block) with systematically tailored compositions of pinene‐based comonomers. We found that the pinane core (which is a constitutional isomer of norbornene) appears to promote ideal behavior with regard to bulk thermal properties of statistical copolymers, which mirrors the behavior of norbornene‐based systems. We also found that block copolymers exhibited thermomechanical properties that were highly tunable (and apparently correlated to carbocycle composition).

ONE-POT SYNTHESIS OF NORBORNENE-CYCLOOCTENE COPOLYMERS

The one-pot synthesis of random multiblock copolymers of norbornene and cyclooctene has been performed for the first time. It is shown that the first generation Grubbs Ru-carbene complex makes it possible to obtain these copolymers directly from monomers. In the course of one-pot synthesis, the metathesis polymerization of norbornene, which has a markedly higher ring strain, occurs first. Then, cyclooctene polymerizes and simultaneously an interchain cross-metathesis reaction takes place, during which the block structure of the copolymer is formed. Compared to the previously studied interaction of polynorbornene and polycyclooctene, the one-pot method makes it possible to obtain copolymers with a higher molar mass at a lower catalyst consumption.

Rational design of aldimine imidazolidin-2-imine/guanidine nickel catalysts for norbornene (Co)polymerizations with enhanced catalytic performance

The development of late transition metal catalysts bearing novel ligand platforms is a convenient pathway to obtain prospective systems with enhanced catalytic performance, however, it remains a challenge in the field of olefin (co)polymerizations. In this contribution, a new family of [N,N]-type of bidentate aldimine imidazolidin-2-imine/guanidine ligands and their nickel complexes Ni1–Ni7 bearing a distinct six-membered chelate ring were successfully synthesized, and characterized. All of the nickel catalysts were active for norbornene polymerization with high activity of up to 7.44 × 105 g mol–1 h−1. These catalysts also copolymerized norbornene and 1-alkenes (1-dodecene and 1-octadecene) while keeping high activities to produce various norbornene-based high-molecular-weight (Mn = 5.75–36.0 kg mol−1) cyclic olefin copolymers (COCs) with adjustable 1-alkene incorporations (1.44–13.30 mol%) and a wide range of Tg values (102.2–271.4 °C). Moreover, with the decoration of bulky N-aryl substituents, these nickel catalysts exhibited strong tolerance towards polar monomer to promote the direct copolymerization of norbornene and methyl 10-undecenoate with high activity (up to 9.88 × 104 g mol–1 h−1), and furnished polar functionalized COCs with a high molecular weight (Mn up to 72.4 kg mol−1) and reasonable polar monomer incorporations (0.19–0.45 mol%). These nickel complexes are rare examples and also promising candidates as catalysts for the efficient synthesis of various COCs.

Copolymerization of Norbornene and Methyl Acrylate by Nickel Catalyst Bearing 2-(Diarylphosphino)-N-phenylbenzenamine Ligands

The synthesis of polar functionalized cyclic olefin copolymers (COCs) from the coordination copolymerization of norbornene (NB) and polar monomers catalyzed by late transition metal catalysts has been a recent research hotspot. However, few catalysts have achieved efficient copolymerization with commercial vinyl-type polar monomers, such as methyl acrylate (MA). In this contribution, nickel complexes bearing 2-(diarylphosphino)-N-phenylbenzenamine ligands were synthesized and applied as pre-catalysts to catalyze the (co)polymerization of norbornene. Upon the activation of methylaluminoxane (MAO), these nickel catalysts were active for norbornene polymerization with the highest activity achieved being 3.6 × 106 g mol−1 h−1 and the highest number average molecular weight (Mn) of polynorbornene (PNB) reaching 27.4 × 105 g mol−1. Moreover, these nickel catalysts also promoted the copolymerization of norbornene and MA to furnish high-molecular-weight NB/MA copolymers (Mn up to 6.20 × 104 g mol−1) with reasonable MA contents (3.07−5.90 mol%). The molecular weight of PNB and NB/MA copolymers obtained by the present nickel catalysts are remarkably higher than those of the (co)polymers from our previous reported dimethyl substituted phosphinobenzenamine nickel catalyst, suggesting significant progress in this field.

Effect of coumarin backbone in N^O type nickel catalyzed olefin polymerization

Designing and synthesis of easily available nickel based catalysts has become an attractive research direction in olefin polymerization. In this contribution, novel coumarin-type N^O nickel catalysts with sterically and electronically varied substituents were synthesized and applied in ethylene polymerization, norbornene homopolymerization and copolymerization. Sterically hindered catalysts Ni2-Ni4 behaved in good performance, generating polyethylene with higher molecular weight. On the other hand, for the norbornene copolymerization process, sterically less hindered Ni1 mediated the higher incorporation ratios both for 5-norbornene-2-carboxylic methyl ester up to 22.2 mol% and 5-norbornene-2-methanol up to 28.9 mol%. The simple synthesis and the possibility of tuning their catalytic properties with Lewis acid addition make this system highly attractive for further exploration.

Alternating Ring-Opening Metathesis Polymerization Promoted by Ruthenium Catalysts Bearing Unsymmetrical NHC Ligands

In this paper, Grubbs- and Hoveyda–Grubbs-type olefin metathesis catalysts featuring N-cyclopentyl/N’-mesityl backbone-substituted N-heterocyclic carbene (NHC) ligands were synthesized. Their propensity to promote the alternating ring-opening metathesis copolymerization (ROMP) of norbornene (NBE) with cyclooctene (COE) or cyclopentene (CPE) was evaluated and compared to that shown by analogous N-cyclohexyl complexes. High degrees of chemoselectivity were achieved in both copolymerizations. The presence of the N-cyclopentyl substituent allowed for the achievement of up to 98% and 97% of alternating diads for NBE-COE and NBE-CPE copolymers, respectively, at low comonomer ratios. Density functional theory (DFT) studies showed that both the sterical and electronic effects of NHC ligands influence catalyst selectivity.

Olefin cross-metathesis of polynorbornene with polypentenamer: New norbornene–cyclopentene multiblock copolymers

Statistical multiblock copolymers of norbornene (NB) and cyclopentene (CP) with different compositions and average block lengths are synthesized via the metathesis of polynorbornene (PNB) with polypentenamer (PCP) mediated by Grubbs’ catalysts of the 1st (G1) and 2nd (G2) generations. Interest in the copolymerization of NB and CP is dictated by the attractive properties of their homopolymers, whereas its realization is hampered by the mismatch in their metathesis polymerization activities. This difficulty can be circumvented by starting from the homopolymers, which are well-known industrial products. Our study demonstrates that the interaction of PNB with PCP in dilute solutions at room temperature in the presence of G1 leads to the copolymers with short CP blocks of 1–3 units separating longer NB blocks. In situ 1H NMR monitoring of the process reveals nearly full depolymerization of PCP via the ring-closing intramolecular metathesis and the formation of NB–CP copolymers presumably via the interaction of CP with PNB. The depolymerization can be suppressed by increasing the concentration of reacting polymers and replacing G1 with more active G2. Under these conditions, the cross-metathesis of PNB with PCP results in the multiblock NB–CP copolymers with composition close to that of the initial homopolymer mixture, but short blocks of the both comonomers. A copolymer with longer blocks that can inherit properties of the parent homopolymers is obtained by decreasing the reaction temperature to 5 °C. Additional information about the structure of NB–CP copolymers is obtained via their hydrogenation followed by spectral and thermal characterization. Thus, the macromolecular cross-metathesis of unsaturated polymers appears to be a versatile method to synthesize copolymers with different backbone structures that are hard to reach by other methods.

Star polymers with norbornene/1-octene gradient copolymer arms synthesized by an ansa-fluorenylamidodimethyltitanium-[Ph3C][B(C6F5)4] catalyst system

Cyclic olefin copolymers (COCs), among which ethylene (E)/norbornene (NB) copolymer have been commercialized, are novel optical plastics but their brittleness narrows their application fields. In this research, star polymers with NB/1-octene (O) gradient copolymer arms and cross-linked cores were synthesized by adding norbornadiene (NBD)/E or 1,11-dodecadiene (DOD) after NB/O copolymerization using a ( t BuNSiMe 2 Flu)TiMe 2 ( I )-[Ph 3 C][B(C 6 F 5 ) 4 ] catalyst system with 2,6-di- tert -butyl-4-methylphenol-treated tri- n -octylaluminum (Oct 3 Al/BHT) as a scavenger. The obtained star polymers possessed the O-rich soft segments close to the core and the NB-rich hard segments in the outer layer. The DOD-cored star polymers had a larger number of arms (15) and a higher star polymer content (68 wt%) than the NBD/E-cored ones (6 and 58 wt%, respectively). The films of the mixtures of the star and the corresponding arm polymers were molded by a melt-pressing procedure. The tensile properties of the films of the DOD-cored star polymer mixtures were significantly improved compared to those of the arm polymers. The Young's modulus, yield stress, strength, and strain at break were controlled by the NB content, the arm length, and the gradient structure of the arms. These results clarified the novelty of the star-shaped NB/ α -olefin copolymers and would expand the application fields of COCs. • Star-shaped polymers with norbornene/1-octene gradient copolymer arms were synthesized by an “arm-first” strategy. • The star-shaped polymers showed two T g values assignable to an octene-rich soft core and a norbornene-rich hard sphere. • Transparent films were obtained from the blend of the star and the arm polymers by melt processing. • The of mechanical properties of the blend films were improved compared with those of the arm polymer films. • The thermal and the star polymers were controlled by the arm length and the norbornene content.

Phosphinobenzenamine Nickel Catalyzed Efficient Copolymerization of Methyl Acrylate with Ethylene and Norbornene

A series of phosphinobenzenamine-based nickel complexes bearing substituted phenylphosphine ligands were synthesized and characterized. These nickel complexes combined with methylaluminoxane (MAO) exhibited very high activity (∼106 g mol–1 h–1) and good thermal stability for norbornene polymerization. The nickel catalysts were able to conduct copolymerization of norbornene and methyl acrylate (MA) with high activity (3.76 × 105 g mol–1 h–1) to give high-molecular-weight functionalized cyclic olefin copolymer (COC) with reasonable MA incorporation (2.39–6.47 mol %). Moreover, the nickel catalysts also promote the copolymerization of ethylene and MA with moderate activity (∼104 g mol–1 h–1) to produce semicrystalline high-molecular-weight polar functionalized polyethylene (PE). The MA incorporation in the copolymer was controlled in a wide range (up to 15.5 mol %). These complexes without any sterically bulky substituent on the ligand are distinctive examples of earth-abundant nickel complexes toward the direct copolymerization of ethylene or norbornene with the challenging vinyl polar monomer MA.

Cyclic olefin copolymers containing both linear polyethylene and poly(ethylene-co-norbornene) segments prepared from chain shuttling copolymerization of ethylene and norbornene

A series of novel HDPE/COC multiblock copolymers have been effectively obtained via chain shuttling copolymerization of ethylene and NBE. These promising copolymers exhibit excellent clarity, high heat resistance and balanced mechanical properties.

Comparison of Aging Resistance and Antimicrobial Properties of Ethylene-Norbornene Copolymer and Poly(Lactic Acid) Impregnated with Phytochemicals Embodied in Thyme (Thymus vulgaris) and Clove (Syzygium aromaticum).

The effects of plant-based extracts on the solar aging and antimicrobial properties of impregnated ethylene–norbornene (EN) copolymer and poly(lactic acid) (PLA) were investigated. In this study, the impregnation yield of polyolefin, lacking in active centers capable of phytochemical bonding, and polyester, abundant in active sides, was measured. Moreover, two different extracts plentiful in phytochemicals—thyme (TE) and clove (CE)—were employed in the solvent-based impregnation process. The effect of thymol and eugenol, the two main compounds embodied in the extracts, was studied as well. Interestingly, oxidation induction times (OIT) for the impregnation of EN with thyme and clove extracts were established to be, respectively, 27.7 and 39.02 min, which are higher than for thymol (18.4 min) and eugenol (21.1 min). Therefore, an aging experiment, mimicking the full spectrum of sunlight, was carried out to investigate the resistance to common radiation of materials impregnated with antioxidative substances. As expected, the experiment revealed that the natural extracts increased the shelf-life of the polymer matrix by inhibiting the degradation processes. The aging resistance was assessed based on detected changes in the materials’ behavior and structure that were examined with Fourier-transform infrared spectroscopy, contact angle measurements, color quantification, tensile tests, and hardness investigation. Such broad results of solar aging regarding materials impregnated with thyme and clove extracts have not been reported to date. Moreover, CE was found to be the most effective modifying agent for enabling material with antimicrobial activity against Escherichia coli to be obtained.

Homo‐ and Copolymerization of Norbornene with Allyl Palladium and Nickel Complexes Bearing Imidazo[1,5‐a]pyridine Sulfonate Ligands

AbstractA series of allyl palladium and nickel complexes based on imidazo[1,5‐a]pyridine sulfonate ligands were synthesized. All these complexes were fully characterized by 1H and 13C NMR, elemental analysis, and high‐resolution mass spectrometry (HRMS). By treatment with Me2AlCl, palladium complexes showed high activities (up to 4.5×107 g of PNB (mol of Pd)−1 h−1) in norbornene polymerization, and the steric hindrance of the catalysts had little effect on the catalytic activities. They could also catalyze the copolymerization of norbornene with butyl vinyl ether (BVE) and ester monomers, but could not catalyze the copolymerization of norbornene with allyl butyl ether (ABE). In addition, the catalytic activities of nickel complexes for norbornene polymerization were similar to that of palladium complexes upon activation with MAO. They could catalyze copolymerization of norbornene with BVE and ABE, but not with ester monomers. In nickel system, the lower steric hindrance of the substituent led to higher activity.

Addition copolymerization of norbornene lactone catalyzed by Pd complexes

AbstractThe addition copolymerization of norbornene (NB) with functionalized monomers can lead to the modification of physical properties of poly(NB). Herein, the synthesis of new copolymer of NB with exo‐norbornene lactone (exo‐NBL) is reported. The copolymerization proceeded by four Pd catalytic systems, and of these, Pd(allyl)IDippCl/AgSbF6 (IDipp = 1,3‐bis[2,6‐diisopropylphenyl]imidazolin‐2‐ylidene)) was the most effective for the incorporation of exo‐NBL. Specifically, the copolymerization with exo‐NBL/NB feed ratio of 50/50 at r.t. by 0.1 mol% of the Pd catalyst produced poly(NB‐co‐exo‐NBL) with Mn of 87,000, and Mw/Mn of 1.2 in 40% yield, incorporating exo‐NBL of 18 mol%. The time–conversion plots and 1H diffusion ordered spectroscopy (DOSY) NMR analysis of the copolymer suggest that it has a random sequence. In contrast, no copolymer was formed from endo‐NBL. This is because of steric hindrance of the endo‐lactone moiety by considering the (co)polymerization of endo‐5‐norbornene‐2‐carboxylic acid methyl ester (endo‐NBCO2Me). The incorporation of exo‐NBL improves the solubility of poly(NB‐co‐exo‐NBL) in several chlorinated solvents and gives high thermal stability with 10% weight loss at a temperature of more than 400°C. Two amorphous halos corresponding to intra‐ and interchain distances were observed in the WAXD patterns, allowing to calculate d‐spacing values, which are higher than that of poly(NB).