Pendant Double Bonds Research Articles

Application of Network Dimension Theory to the Kinetics of Nanogel Formation in Miniemulsion Vinyl/Divinyl Copolymerization: Free‐Radical and Living Polymerization

AbstractIn vinyl/divinyl copolymerization, a crosslink is formed by the reaction between an active center and a pendant double bond. When both the active center and the pendant double bond are located within the same polymer molecule, the cyclization occurs, which is ineffective for growth in molecular weight. In the present model, the network dimension theory is applied to estimate the mean‐square radius of gyration for the growing polymer molecule, which is used to account for the enrichment effect of pendant double bonds around the active center for the cyclization reaction. The model is applied to the miniemulsion copolymerization, and both conventional free‐radical polymerization and ideal living polymerization are considered. Some of important characteristics of network architecture formed in these two types of polymerization mechanisms that cannot be predicted based on the classical chemical kinetics can be reproduced by the model, such unique characteristics as the pendant double bonds are consumed from the beginning of polymerization in the conventional free‐radical polymerization but not so in the living polymerization. The present model provides useful insights into the size and structural dependent network formation kinetics without relying on the lattice model.

A lysine and amide functionalized polymer-based polar stationary phase for hydrophilic interaction chromatography

A novel polymer-based polar stationary phase for hydrophilic interaction chromatography (HILIC) is described. It was obtained by grafting lysine and acrylamide onto poly (glycidyl methacrylate-divinylbenzene) (GMA-DVB) microspheres via ring-opening reaction of epoxy groups and free radical polymerization with pendant double bonds of the microspheres. Multiple types of polar groups including zwitterionic (carboxylate and amine), amide and diol onto the microspheres make them highly hydrophilic. It showed typical HILIC character and good separation performance towards model polar analytes. Negligible bleed level under gradient elution mode (up to 50% fraction of water) was observed. It also exhibited specific separation selectivity to ionic analytes and simultaneous separation of anions and cations could be achieved in ideal electrostatic selectivity elution order, e.g. I−< NO3− <Br− <Cl− or K+< Na+ < Li+.

On the Absence of Cyclic Structures in Branched Polystyrenes Synthesized by Living Three-Dimensional Radical Polymerization in the Medium of a Deteriorating Thermodynamic Quality Solvent

Branched polystyrenes are synthesized by the radical copolymerization of styrene and divinylbenzene with reversible inhibition (in the presence of 2,2,6,6-tetramethylpiperidine-1-oxyl) under deteriorating thermodynamic quality of the solvent. The resulting polymers are studied by size-exclusion chromatography combined with static light scattering, ozonolysis, NMR spectroscopy, and differential scanning calorimetry. The branched polymers synthesized by living radical polymerization are characterized by lower intrinsic viscosity values than their linear analogs. Kuhn–Mark–Houwink parameters for these polymers in a tetrahydrofuran solution (а = 0.29) confirm the nonlinear architecture of macromolecules and a high content of pendant double bonds comparable in the order of magnitude with their theoretical content in the absence of the cyclization reaction indicate their branched structure. The glass transition temperature of the branched polystyrenes is 20–35°С lower than the glass transition temperature of the linear polystyrene.

Critical conditions for liquid chromatography of statistical polyolefins: Evaluation of diene distribution in EPDM terpolymers

Liquid chromatography at critical conditions is of interest as it may unravel molecular information on macromolecular structures not accessible by any other analytical techniques. Yet so far, such conditions have never been experimentally established for copolymers, where a particular need for such information exists. Toward this goal, critical conditions for statistical ethylene propylene copolymers were identified. In the first approach the composition of the binary mobile phase was varied at a constant temperature, and secondly by modulating the adsorption-desorption temperature at constant mobile phase composition. Solvents for both methods were identified by using a novel approach that combines structure retention relationships with Hansen Solubility Parameters. As a result, for the first time, the heterogeneity of an ethylene propylene diene terpolymer sample with regard to the pendant double bond of the diene could be determined. The novel chromatographic approach was validated by measuring the composition of fractions taken over the chromatographic run offline by nuclear magnetic resonance. In summary, this work gave the first experimental evidence for the existence of critical conditions for polyolefin random copolymers, as postulated by Brun. This novel chromatographic approach holds immense potential to engineer complex polymers towards future applications by making use of the now-accessible molecular information.

Chemoselective and controlled ring-opening copolymerization of biorenewable α-methylene-δ-valerolactone with ε-caprolactone toward functional copolyesters

Functional P(MVL-co-CL) copolyesters with modifiable pendent double bonds were obtained by chemoselective and controlled ring-opening copolymerization of biorenewable MVL with CL using an organophosphazene/urea binary catalyst.

Self-healing polyester elastomer with tuning toughness and elasticity through intermolecular quadruple hydrogen bonding

It is a desirable to prepare high performance polyester elastomers that possess high strength, good elasticity and efficient self-healing capability. Herein, we report the preparation of such elastomers based on aliphatic polyesters cross-linked by UPy-UPy quadruple hydrogen bonding. A functional monomer α-methylene-γ-butyrolactone (MBL) was copolymerized with ε-caprolactone (ε-CL) to give pendent double bonds functionalized copolyester precursors, which were subject to post-modification with UPy groups via the efficient thiol-ene click reaction. Then, the self-healing polyester elastomers were finally obtained by tuning the molecular weight of precursors, the contents of UPy units and crystallization behaviors. The results show that high polyester molecular weight, moderate UPy content and inhibition of crystallization are helpful to improve the mechanical and self-healing properties of elastomers. The obtained elastomers show good mechanical strength (1.0–1.5 MPa), excellent elongation at break (970–1560 %) and toughness (9.6–11.9 MJ/m3), and have the rapid self-healing property (>70 % after healing at 60 °C for 2 h), displaying great potential in biomedical applications.

Functional and degradable copolyesters by ring-opening copolymerization of epoxides and anhydrides

The ring-opening copolymerization (ROcoP) of epoxides and anhydrides is exploited to afford 4 structurally diverse and functional copolyesters. Mixtures of 2 epoxides (allyl glycidyl ether and butylene oxide) with 1 anhydride (succinic, glutaric, phthalic and homo phthalic anhydride) are copolymerized in the presence of bis(triphenylphosphine)iminium chloride (PPNCl) as organocatalyst. All monomer combinations yield vinyl-functionalized materials with alternating epoxide-anhydride units, statistical incorporation of both epoxides along the polymer chain and molar masses up to 28.3 kg/mol. The copolyesters are amorphous with a Tg between –39 °C and 38 °C. Together with the molar mass, the anhydride dictates the thermal stability of the copolyesters with glutaric anhydride resulting in a remarkably high thermal stability up to 310 °C. In a post-polymerization step, the pendant double bonds are radically crosslinked to gels with swelling ratios above 1500 % and comparable to enhanced thermal stability with respect to the non-crosslinked, parent copolyesters. The degradation of the 4 copolyesters (before and after crosslinking) is tested in abiotic and enzymatic conditions: The highest degradation rates are observed for the non-crosslinked materials in enzymatic conditions with a mass loss of up to 60 % after 27d. After crosslinking, the gels are more stable against degradation under both conditions, although a decrease in the gel content and a decrease in mass indicates that degradation still takes place.

ARGET ATRP of ethylene glycol dicyclopentenyl ether methacrylate with vegetable oil and terpene‐derived methacrylic monomers

AbstractHomo and statistical copolymerization reactions of ethylene glycol dicyclopentenyl ether methacrylate (EGDEMA) and a vegetable‐oil based methacrylic ester C13MA (average alkyl chain length = 13) are studied via activator regenerated electron transfer polymerization (ARGET ATRP) using only trace amounts of copper catalyst. Poly(EGDEMA) and poly(C13MA) homopolymers and statistical poly(EGDEMA‐stat‐C13MA) copolymers are cleanly synthesized with monomodal molecular weight distribution and dispersities Đ = Mw/Mn = 1.39–1.76 and Mn ~ 12 kg/mol. Chain end fidelity is confirmed by chain extension from poly(C13MA) macroinitiator with EGDEMA to make poly(C13MA‐b‐EGDEMA) diblock copolymers, which exhibit two distinct glass transition temperatures (Tgs), one for the poly(C13MA) block (−39°C) and the other for the poly(EGDEMA) block (23.9°C), suggesting microphase separation. Due to the relatively low Tg of poly(EGDEMA‐stat‐C13MA), terpene‐derived isobornyl methacrylate (IBOMA) is copolymerized with EGDEMA forming poly(EGDEMA‐stat‐IBOMA) statistical copolymers with Tgs ranging from 22.9–113°C. Additionally, crosslinking of the poly(EGDEMA) homopolymer and poly(EGDEMA‐stat‐C13MA) and poly(EGDEMA‐stat‐IBOMA) copolymers is achieved by UV thiol‐ene clicking of the pendent double bonds of EGDEMA units with suitable dithiols at 365 nm. For poly(EGDEMA), conversion of the thiol‐ene click reaction reaches 70%; where as the conversion of the clicking reactions is higher in the copolymers with a conversion up to 92% for poly(EGDEMA‐stat‐C13MA) and 97% for poly(EGDEMA‐stat‐IBOMA).

Synthesis of syndiotactic polystyrene—Polyisobutylene graft copolymers by cationic half‐sandwich scandium complex

AbstractSyndiotactic polystyrene is a high strength engineering plastic, and polyisobutylene is an excellent elastomers. In order to combine the advantages of syndiotactic polystyrene and polyisobutylene, isobutylene was achieved to graft onto the crystalline syndiotactic polystyrene, forming graft copolymers, under half sandwich scandium complex [(C5Me4SiMe3)Sc(CH2SiMe3)2THF]/[Ph3C][B(C6F5)4] after the application of syndiotactic copolymers of styrene and 4‐isopropenylstyrene with pendant double bonds. Grafted copolymers based on crystalline polystyrene and rubbery polyisobutylene block have both high Tm (270°C) and low Tg (−67°C), meanwhile, these materials have relative good mechanical properties.

Preparation of an anion stationary phase modified by quaternary ammoniated allyl glycidyl ether

制备了一种季铵化烯丙基缩水甘油醚(allyl glycidyl ether, AGE)改性聚合物基质的阴离子固定相应用于离子色谱系统。它是利用AGE与水解的聚甲基丙烯酸缩水甘油酯-二乙烯基苯(poly(glycidylmethacrylate-divinylbenzene, GMA-DVB)微球表面残留双键通过表面自由基共聚,再通过N,N-二甲基乙醇胺(一种叔胺)进行开环反应制备得到的。通过考察有机叔胺类型、微球水解、单体和引发剂用量、反应温度和时间对7种阴离子分离性能的影响,优化了制备条件。采用扫描电镜、元素分析对所得阴离子固定相进行了表征。结果表明,采用预先水解的GMA-DVB微球(水解过程中微球表面丰富的环氧基团转化为羟基)相对于直接采用GMA-DVB微球有助于降低固定相的交换容量和微球自身的非离子吸附作用;通过淋洗液浓度和目标离子保留因子的拟合结果证实了该固定相保留机理为典型的离子交换作用。使用碳酸根淋洗液,在优化的色谱条件下,该固定相可在13 min内实现常见7种无机阴离子的基线分离,并表现出较高的柱效(Cl-理论塔板数为49000块/m)。该色谱柱实用性通过分析自来水实际样品进行了验证。

Enzymatic synthesis, post-polymerization modification and cross-linking of functionalized poly(β-thioether ester) with pendant vinyl group

Vinyl-functionalized poly(β-thioether ester) (PVTE) was synthesized by enzyme-catalyzed polymerization using immobilized lipase B from Candida antarctica (CALB) for the first time. Four different functionalized monomers were prepared and three polymerization strategies including polycondensation (PC), ring-opening polymerization (ROP), and ring-opening and condensation copolymerization (ROCCP) were investigated. The influences of reaction conditions such as polymerization temperature, time, and monomer ratio on the molecular weight of functionalized poly(β-thioether ester)s were also studied. Both the homopolymer and copolymers were characterized by NMR, SEC, TGA and DSC. Moreover, these poly(β-thioether ester)s containing pendant double bonds toward postfunctionalization were demonstrated by photoinitiated thiol-ene click chemistry and Michael addition reaction, providing a way to cross-linked polyester gels.

Coordination Polymerization of Renewable (E)‐4,8‐Dimethyl‐1,3,7‐Nonatriene by Rare‐Earth Metal Catalysts

Comprehensive SummaryCoordination polymerization of renewable (E)‐4,8‐dimethyl‐1,3,7‐nonatriene (DMNT) has been performed using pyridyl‐methylene‐ fluorenyl scandium complex 1, half‐sandwich scandium complex 2, diiminophosphinato rare‐earth metal complexes 3a—3c and 4a—4b, bis(phosphino)carbazolide yttrium complex 5 and β‐diketiminato yttrium complex 6. Fluorenyl scandium complexes 1 and 2, activated by [Ph3C][B(C6F5)4] and AliBu3, are moderately active and show perfect 1,2‐regioselective (1,2 &gt; 99%). Conversely, asymmetric diiminophophinato complexes 3a—3c promote the DMNT polymerization to produce high trans‐1,4 regulated products with the activity trend: Sc &lt; Lu &lt; Y. Complexes 4—6 are virtually inactive for the DMNT polymerization although they are highly active in isoprene polymerization. A diblock copolymer bearing 3,4‐polyisoprene block and trans‐1,4‐poly(DMNT) block is obtained using complex 3c in one‐pot reaction. Hydrogenation of trans‐1,4‐poly(DMNT) affords an elastomer with a Tg of –10°C. The epoxidation reaction of trans‐1,4‐poly(DMNT) with 3‐chloroperbenzoic acid transfers the pendant double bonds in the cis configuration into the epoxy groups.

Photonic crystal films with upconversion luminescence based on the self-assembly of polystyrene encapsulated NaYF4:Ln3+ composite microspheres for dual-mode optical code

The design and fabrication of advanced materials with multiple optical states for constructing security code are of great value in anti-counterfeiting. Herein, novel upconversion photonic crystal (UCPC) films with tunable luminescence and structural color were prepared by vertical deposition of polystyrene encapsulated NaYF4:Ln3+ (CSNPs@SiO2/PS) composite microspheres. The composite microspheres were synthesized by sequential coating technology. Firstly, NaYF4:Ln3+@NaYF4 core/shell nanoparticles (CSNPs) were synthesized and served as upconversion luminescent emission centers. Then, the CSNPs were further coated by a SiO2 shell with pendant double bond to form CSNPs@SiO2-MPS. Afterward, mono-dispersed CSNPs@SiO2/PS composite microspheres were synthesized by emulsion polymerization of styrene in the presence of CSNPs@SiO2-MPS. By tailoring the doped lanthanide ions in CSNPs and adjusting the diameter of the composite microspheres, UCPC films with diverse upconversion fluorescence and structural color can be obtained. As a proof of concept, these different kinds of UCPC films were employed as information coding units to construct dual-mode anti-counterfeiting code. Our protocol provided a new security strategy for information storage.

Characterization of ethylene-propylene-diene terpolymers using high-temperature size exclusion chromatography coupled with an ultraviolet detector

The distribution of the pendant double bond along the molar mass axis impacts the vulcanization behavior of ethylene-propylene-diene (EPDM) terpolymers. Yet, the analysis of this parameter has so far been hampered by the lack of suitable detection methods. Towards this goal we have investigated the potential of ultraviolet detector (UV) detection for high temperature size exclusion chromatography of EPDM terpolymers containing 5-ethylidene-2-norbornene (ENB), dicyclopentadiene (DCPD), and vinyl norbornene (VNB) as termonomer. The influence of termonomer structure and experimental parameters such as, mobile phase, analyte concentration and temperature on the spectroscopic response was probed. EPDM containing ENB showed a significantly stronger UV-absorption compared to terpolymers with VNB and DCPD. The absorbance was found to correlate with the sample concentration approaching signal saturation at higher ENB content. Generally, temperature did not have any significant effect on the UV absorbance of EPDM. Based on the results, a method was developed, which can profile the content of ENB along the molar mass axis. An evaporative light scattering detector (ELSD) was employed to monitor the analyte concentration, in combination with the UV detector, to quantitatively measure the distribution of ENB content along the molar mass distribution. This work could be feasible for the other two commercial relevant termonomers DCPD and VNB.

Vinylic addition poly(norbornene-co-alkenylnorbornenes) synthesized with benzylic palladium catalysts: materials for manifold functionalization

Functional groups can be easily attached to robust vinylic addition polynorbornenes by the transformation of the pendant double bond of new efficiently synthesized copolymers.

Improved respond speed of thienylene-phenylene electrochromic polymer with pendent double bond structure

A hybrid thienylene-phenylene conjugated molecule with pendent double bond unit on side chain, 5,5'-(2,5-bis(hex-5-en-1-yloxy)-1,4-phenylene)bis (2,3-dihydrothieno[3,4-b] [1,4] dioxine) (EDOT-ene-BE), was designed, and its corresponding polymer poly(EDOT-ene-BE) with similar-network structure was prepared by electrochemical method. The introduction of pendent double bond unit has little influence on the optical absorption and oxidation potential of EDOT-ene-BE. The pendent double bond unit could be attached on polymeric chain of poly(EDOT-ene-BE), leading to linear polymeric chain turning into similar-network structure. The microstructure makes poly(EDOT-ene-BE) film exhibit faster respond speed and higher coloration efficiency than poly(EDOT-BE) without pendent double bond unit. The kinetics indicate that poly(EDOT-ene-BE) could switch between oxidation and reduction states in 0.4 s, which is among one of the fastest respond times. After annealing, the polymerization between pendent double bond units leads to the formation of poly(EDOT-BE-net) with network molecular structure. As poly(EDOT-ene-BE), poly(EDOT-BE-net) possesses faster respond speed relative to poly(EDOT-BE), however, the respond speed is slower than that of poly(EDOT-ene-BE). These results demonstrate that the introduction of pendent double bond unit in side chain results into the formation of similar-network molecular structure, which is proved to be an effective strategy to improve the properties of polymer electrochromic materials.

Farnesene and norbornenyl methacrylate block copolymers: Application of thiol-ene clicking to improve thermal and mechanical properties

Novel block copolymers were synthesized for the first time via nitroxide-mediated polymerization (NMP) using ethylene glycol dicylopentenyl methacrylate (EGDEMA), which has a pendent double bond in the norbornene group, and farnesene (Far), a terpene-based diene. Homopoly(EGDEMA)) was synthesized successfully using Dispolreg 007 initiator without any co-monomer as typically required of NMP, and the macroinitiator was chain-extended with Far making poly(EGDEMA-b-Far) diblock copolymers. Due to the relatively low glass transition temperature (Tg) of poly(EGDEMA), the methacrylate block was also copolymerized statistically with isobornyl methacrylate (iBOMA) to add stiffness, then chain-extended with Far. Additionally, the pendent double bond of EGDEMA allowed for thiol-ene clicking of POSS units for further functionalization of these block copolymers. However, the conjugation efficiency of the thermally initiated thiol-ene clicking was low and resulted in low POSS incorporation (1.6–10 mol%), especially for block copolymers that included iBOMA due to its increased stiffness and steric hindrance. Nonetheless, the added POSS improved the thermal stability by minimizing the degradation of the 1,4-addition Far units, as well as the degradation of isobornyl units of iBOMA. The mechanical strength was also increased as POSS units reinforced the physical crosslinks of these block copolymers as shown by an increase in linear viscoelastic regions. Distinct Tgs were observed for the respective elastomeric poly(Far) block (~-70 °C) and thermoplastic block (30 °C for poly(EGDEMA) and 110 °C for poly(EGDEMA-co-iBOMA)), therefore suggesting microphase separation. An increase in Tg was also observed in all polymers with added POSS, further confirming the added stiffness provided by POSS. These poly(EGDEMA-b-Far) and poly(EGDEMA-co-iBOMA-b-Far) show great versatility as alternative TPE materials, with improved mechanical and thermal properties added by functionalization of POSS.

Gel Point Properties in Batch Free‐Radical Vinyl/Divinyl Copolymerization

AbstractGelation is a critical phenomenon, and various simple relationships are expected to hold. On the other hand, it is important to clarify the required conditions for the validity of the relationships. In this theoretical study, the effects of the primary chain connection statistics and the primary chain length distribution change during batch free‐radical vinyl/divinyl copolymerization on the gel point properties are investigated systematically. The weight fraction distribution at the gel point always conforms to the power‐law distribution,W(P)∝P−αwith α = 1.5, as long as the classical chemical kinetics is valid in a closed reaction system. When the primary chain connection statistics is independent of chain length, the cross‐linking density, ρg, of the gel molecule right at the gel point is given by , where is the weight‐average chain length of all primary chains. The random cross‐linking is a special case that belongs to this category. The distribution of the pendant double bonds among polymer molecules having different molecular weights is nonrandom, except for the special cases with equal reactivity of all types of double bonds for which the random cross‐linking applies.

Preparation and evaluation of a polymer-based sulfobetaine zwitterionic stationary phase

We describe a polymer-based sulfobetaine zwitterionic stationary phase for hydrophilic interaction liquid chromatography (HILIC). It was prepared by grafting acrylamide-type sulfobetaine monomer instead of common methacrylate-type sulfobetaine onto hydrolysed poly (glycidyl methacrylate-divinylbenzene) (GMA-DVB) microspheres via pendant double bonds of DVB. The phase has been characterized by elemental analysis, scanning electron micrograph and N2 adsorption-desorption experiment. It shows wider pH tolerance range (from 2 to 12) and excellent separation ability towards common strong polar analytes such as nucleosides and nucleic bases, water-soluble vitamins, amino acids, inorganic anions and cations. Notably, it exhibits negligible baseline noise level (~0.15 pA) under typical HILIC mobile phase. Excellent selectivity in separation of α- and β-anomers of reducing sugars and lactose/lactulose has also been observed.

A hydrolytically stable amide polar stationary phase for hydrophilic interaction chromatography

A novel amide functionalized polar stationary phase has been described by grafting acrylamide polymer coating onto hydrolysed poly (glycidyl methacrylate-divinylbenzene) (GMA-DVB) microsphere. The grafting of acrylamide coating is performed via free radical polymerization of acrylamide with pendant double bonds of hydrolysed GMA-DVB microsphere. The obtained stationary phase (G-pAM) possesses favorable hydrophilicity, as proved by strong retention and good separation ability towards several types of model polar analytes (e.g. 71913 plates/m plate count of sucrose), and excellent hydrolytically stability, as indicated by extremely low bleed level (much superior to commercial ones, ~23.7-fold–~77.4-fold lower). Negligible baseline drift under gradient elution (water fraction even up to 50%) was observed. It also exhibits good selectivity in the separation of isomers and homologue sugars.