3 - Manufacture

Some quenched and annealed samples of tetrafluoroethylene copolymers containing perfluoropropyl vinyl ether, perfluoromethyl vinyl ether, and hexafluoropropene were studied by small-angle X-ray scattering and differential scanning calorimetry. Small-angle X-ray scattering experimental spectra were analyzed by a fitting method with the profiles calculated from some theoretical distribution models of the lamellar thickness. The mathematical evaluation of small-angle X-ray scattering patterns has provided crystallinity values which were compared with those obtained by wide-angle X-ray scattering in order to obtain information on the organization of the lamellar stacks. The experimental results allow one to conclude that, during the annealing of the quenched fluorinated copolymers, at increasing temperatures, the melting of the thin lamellae takes place together with the appearance and the growth of nonlamellar crystallites.

Fluorosurfactants are an integral part of many industrial processes due to their unparalleled surface activity and high water and oil repellency and can be found in a wide range of consumer products. However, their lack of biodegradability causes great environmental concern and has led to increased regulatory action in recent years. In the search for alternatives, perfluoropropyl vinyl ether was recently identified as a promising building block with an improved ecological profile regarding degradation and accumulation. Here, we utilized short-chain perfluoropropyl vinyl ether (PPVE) or perfluoromethyl vinyl ether (PMVE) as precursors to construct polyether-based fluorosurfactants through copolymerization with hydrophilic comonomers. Surfactant properties and overall fluorine content per molecule could be easily adjusted by changing the comonomer feed. The surface activity was investigated in aqueous solution via tensiometry and was found to be competitive with both legacy PFAS such as perfluorooctanesulfonic acid and current state-of-the-art small molecule fluorosurfactants (γstat ≥ 20.35 mN m–1). These findings illustrate the potential of amphiphilic copolymers as a modular, straightforward, and versatile platform for next-generation fluorosurfactants as an alternative to long-chain legacy PFAS.

ABSTRACTHerein, we clarified the ring‐expansion cationic polymerization with a cyclic hemiacetal ester (HAE)‐based initiator was versatile in terms of applicable vinyl ether monomers. Although there was a risk that higher reactive vinyl ethers may incur β‐H elimination of the HAE‐based cyclic dormant species to irreversibly give linear chains, the polymerizations were controlled to give corresponding cyclic polymers from various alkyl vinyl ethers of different reactivities. Functional vinyl ether monomers were also available, and for instance a vinyl ether monomer carrying an initiator moiety for metal‐catalyzed living radical polymerization in the pendant allowed construction of ring‐linear graft copolymers through the grafting‐from approach. Furthermore, ring‐based gel was prepared via the addition of divinyl ether at the end of the ring‐expansion polymerization, where multi HAE bonds cyclic polymers or fused rings were crosslinked with each other. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3082–3089

Absolute rate coefficients for the reaction between OH radicals and perfluoro propyl vinyl ether (PPVE) were obtained using the technique of pulsed laser photolysis with the detection of OH radicals by laser induced fluorescence. Rate coefficients were measured over a range of temperatures (212-298 K) and at either 50 or 200 Torr bath-gas (N2 or N2/O2). The temperature dependence of the rate coefficient is given by k1(212-298 K) = (4.88 ± 0.49) × 10(-13) exp[(564 ± 10)/T] cm(3) molecule(-1) s(-1) with a value at room temperature of (3.4 ± 0.3) × 10(-12) cm(3) molecule(-1) s(-1). No pressure dependence was observed, indicating that the reaction is at the high pressure limit under atmospheric conditions. The accuracy of the rate coefficient obtained was enhanced by on-line optical absorption measurements of PPVE at 184.95 nm using a value of σ(184.95 nm) = (5.64 ± 0.28) × 10(-18) cm(2) molecule(-1) determined in this work. An atmospheric lifetime of a few days for PPVE was calculated. Extensive quantum chemical calculations as a complement to the experimental work are presented in order to determine its probable tropospheric degradation mechanism.

Dimerization of perfluoropropyl vinyl ether during the pyrolysis of hexafluoropropylene oxide dimer

Frontal polymerization (FP) of epoxy monomers is typically achieved with a radical‐induced cationic frontal polymerization (RICFP) process that combines a thermal radical initiator with an onium salt superacid generator. In this paper, we show that both thermal and UV‐initiated cationic frontal polymerizations are possible for common epoxy and vinyl ether monomers with only an iodonium superacid generator in the absence of a standalone thermal radical initiator. Increasing superacid generator concentration resulted in an increase in front velocity, as did the addition of vinyl ether to epoxies. The front velocity is reduced by the addition of 4‐methoxyphenol (MeHQ), indicating free‐radicals play a significant role.

A new series of chiral liquid‐crystalline poly(vinyl ether)s was synthesized by cationic polymerization of the corresponding vinyl ether monomers. They consisted of a biphenyl mesogenic unit bearing an (S)‐2‐methylbutyl chiral substituent and spaced via an alkyl segment of varying number x of methylene groups. Different initiators and experimental conditions were used for the polymerization reactions. All the samples were semicrystalline, and smectic C and A sequential mesophases were formed in polymers comprising a sufficiently long spacer segment (x > 8). X‐ray diffraction measurements were performed on unoriented specimens. In the smectic C phase, the occurrence of different orders of X‐ray reflection on the smectic layers enabled drawing of the electron density profiles along the layer normal. By simple model considerations it was possible to choose the most physically acceptable one and to identify the low temperature mesophase as double layer smectic C.

Summary: The perfluorinated copolymer poly(tetrafluoroethylene‐co‐hexafluoropropylene) (FEP) was electron beam irradiated under vacuum at various temperatures ranging from room temperature to a temperature above the melting temperature of FEP. Changes of the chemical structure were analyzed by 19F solid‐state NMR and IR spectroscopy. Trifluoromethyl end groups were generated as a result of main chain scission at all irradiation temperatures studied. In addition, trifluoromethyl side groups in various environments and double bond structures were formed. Quantitative analysis showed that long‐chain branches were formed at irradiation temperatures above 200 °C. Furthermore, the hexafluoropropylene (HFP) units in FEP were found to be less sensitive to radiation than the perfluoropropyl vinyl ether (PPVE) units in poly[tetrafluoroethylene‐co‐(perfluoropropyl vinyl ether)] (PFA).19F solid‐state NMR spectra of FEP.magnified image19F solid‐state NMR spectra of FEP.

A comparative study has been made of the radiation grafting of styrene onto poly(tetrafluoroethylene‐co‐perfluoropropyl vinyl ether) (PFA) and polypropylene (PP) substrates, using the simultaneous irradiation method. Effects of grafting conditions such as monomer concentrations, type of solvent, dose rate and irradiation dose on the grafting yield were investigated. Under the same grafting conditions it was found that a higher degree of grafting of styrene was obtained using a mixture of dichloromethane/methanol solvents for PFA and methanol for PP and the degree of grafting was higher in PP than in PFA at all doses. However, the micro‐Raman spectroscopy analysis of the graft revealed that, for the same degree of grafting, the penetration depth of the grafted polystyrene into the substrate was higher in PFA than in PP substrates. In both polymers the crystallinity was hardly affected by the grafting process and the degree of crystallinity decreased slightly with grafting dose. The dependence of the initial rate of grafting on the dose rate and the monomer concentration was found to be 0.6 and 1.4 order for PFA and 0.15 and 2.2 for PP, respectively. The degree of grafting increased with increasing radiation dose in both polymers. However, the grafting yield decreased with an increase in the dose rate. The increase in the overall grafting yield for PFA and PP was accompanied by a proportional increase in the penetration depth of the graft into the substrates. Copyright © 2003 Society of Chemical Industry

Highly ordered densely crosslinked liquid crystalline poly(vinyl ether) films have been prepared by in situ photopolymerization of oriented bifunctional mesogenic vinyl ether monomers. Orientation was achieved by a simple surface treatment, using a unidirectionally rubbed polyimide film. Polymerization from various monomer phases resulted in LC polymer network films with different molecular organizations. The films were analyzed with small-angle x-ray scattering, polarized light microscopy and infrared-dichroism measurements. It was shown that films with nematic, smectic A and smectic B structures were obtained, the latter having a very high degree of orientation.

<strong class="journal-contentHeaderColor">Abstract.</strong> Absorption cross-sections (ACS) of emerging greenhouse gases (GHG) were measured to estimate the radiative efficiencies (RE) using high-resolution Fourier transform infrared spectroscopy (HR-FTIR). For quantitative spectroscopy, the Beer&ndash;Lambert parameters of absorber pressure, temperature, and optical pass length (OPL) have been accurately determined to be traceable to the primary standards. The OPL of the multipass cell (MP) mounted on the HR-FTIR spectrometer was spectroscopically calibrated. A ratio of the averaged N₂O absorptions was measured in the range of 2,217.4&ndash;2,219.0 cm^-1 with a spectral resolution of 0.026 cm^-1, yielding a ratio of OPLs between the MP and reference cell (RC). This cell-to-cell comparison (CC) method does not include the uncertainty in the referring line strength, thereby reducing the calibration uncertainty compared with a direct line-strength referring method. With the OPL-calibrated MP (3.169 &plusmn; 0.079 m), the ACSs were measured at low absorber pressures with a spectral resolution of 2 cm^-1, integrated at 10 cm^-1 intervals, and multiplied by the new narrow band model to yield the RE values. The RE values of the classic GHGs CF₄, SF₆, and NF₃ were evaluated to be 0.085 &plusmn; 0.002, 0.573 &plusmn; 0.016, and 0.195 &plusmn; 0.008 W m^-2 ppb^-1, respectively, which are consistent with previously reported values. For the emerging GHGs, the RE values were determined to be 0.201 &plusmn; 0.008 W m^-2 ppb^-1 for (CF₃)₂CFCN (heptafluoroisobutyronitrile, commercially referred to as <em>Novec-4710</em>), 0.328 &plusmn; 0.013 W m^-2 ppb^-1 for CF3OCFCF2 (perfluoro methyl vinyl ether, PMVE), and 0.544 &plusmn; 0.022 W m^-2 ppb^-1 for CF₃OCF₂CF₃ (1,1,1,2,2-pentafluoro-2-(trifluoromethoxy)ethane, PFMEE).

Hydrogenated nitrile rubber (HNBR) and a ternary copolymer of vinylidene fluoride, tetrafluoropropylene, and perfluoromethyl vinyl ether (FKM) were blended and vulcanized rubbers that have the excellent low temperature characteristics and oil resistance were successfully obtained. The results of dynamic mechanical analysis demonstrated the great improvement of low temperature characteristics for one of the polymer blend materials (FKM/HNBR = 30/70). Subsequently, the structures of the polymer blends were analyzed by using atomic force microscopy (AFM) and transmission electron microscopy (TEM). The results of AFM and TEM showed that the polymer blend materials have phase‐separated structures with the sea‐island morphology. The sea regions were HNBR and the island regions were FKM for the samples containing less than 50% of FKM. On the other hand, the sea region was FKM for the sample containing 70% of FKM. Even in the stretched polymer blend, no gap or crazing was observed at the interface of FKM and HNBR. Therefore, some kind of strong bonding was presumed to exist between the two types of phases. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 149–156, 2005

Event Abstract Back to Event Glow-discharge radio frequency plasma polyether and fluoropolyether coated substrates prevent IgG protein adsorption Marvin M. Mecwan1* and Buddy Ratner1* 1 University of Washington, Bioengineering, United States Introduction: Protein-based pharmaceuticals present unique challenges in processing, packaging and delivery. All proteins rapidly adsorb to solid surfaces, essentially irreversible, and frequently leads to denaturation or aggregation of the protein. Also, there are concerns with substances from the packaging leaching out and affecting proteins. This study examines fundamental aspects of protein interactions with surfaces, particularly using glow discharge plasma-treated surfaces which can be readily applied to delivery devices, packaging and processing equipment [1],[2] and may lead to a new generation of surfaces effective for protein manufacture, storage and delivery. This research particularly focuses on plasma tetraglyme (TG), acrylic acid (AA), perfluoropropylene (C3F6), and perfluoromethyl vinyl ether (C3F6O) plasma treated glass, stainless steel, and cyclic olefin polymer (COP) substrates and their interaction with IgG. Methods: Glass and COP (8mm φ discs), and 316L stainless steel (7 x 7 mm2) substrates were sequentially cleaned with DCM, acetone, and methanol in a sonication bath for 10 mins x 2. RF-Plasma deposition and delamination: Substrates were loaded into the reactor, and argon etched (40W for 5 min). Using a mass flow controller, the monomer of choice was introduced into the chamber and were plasma deposited. Plasma-treated samples (n=3/group) were washed using DI water x 3 over 24 hours to assess whether coatings would delaminate. ESCA analyses were done using an S-Probe ESCA (with monochromatic Al K-alpha X-rays focused to 800µm spot size) using survey and detailed C1s scans. Data was analyzed using ESCA analysis software. IgG adsorption studies: Bovine IgG was tagged using an ICl method. Plasma-treated samples (n=3/treatment group) were immersed in 0.1mg/mL I-125 tagged bovine IgG solution in 1x cPBS with sodium iodide (cPBSI) for 1 hr. Samples were rinsed with cPBS x 3 and counted for 10 mins using a gamma counter. Cytotoxicity studies: Plasma-coated samples were eluted in complete growth medium for 24 hrs (370C, 5% CO2­ incubator). ~80% confluent NIH-3T3 fibroblasts were exposed to eluates from the plasma coated substrates, and observed over 48 hrs using an inverted microscope. ISO 10993-5 guidelines were used for cytotoxic evaluation. Results and Discussion: ESCA scans of plasma-treated substrates showed absence of substrate associated peaks (such as Fe or Si), suggesting that coatings did not delaminate; also implies that plasma coatings on substrates are at least 10 nm thick (ESCA resolution is 100Å). Furthermore, experimental and theoretical elemental compositions of the surfaces align well. Protein adsorption studies show that tetraglyme and acrylic acid plasma coatings are essentially non-fouling (<2 ng/cm2) as compared to C3F6 and C3F6O plasma coatings which adsorbed proteins in the range of 10-14 ng/cm2. Furthermore, all plasma treated substrates show reduced protein adsorption compared to untreated controls. Moreover, fibroblasts exposed to all plasma coating eluates remained viable after 48 hours. Conclusions: The data demonstrate that plasma-treated polyether and fluoropolyether substrates can create a new generation of surfaces that can be used for contact with protein therapeutic agents.Future studies will be aimed at investigating the strength of bonding of IgG to these surfaces, as well as protein aggregation studies. Winston Ciridon; Xia Dong, PhD

Highly cross-linked poly(styrene sulfonic acid)-grafted poly(tetrafluoroethylene- co-perfluoropropyl vinyl ether) (PFA- g-PSSA) membranes with various thicknesses have been successfully prepared through the simultaneous irradiation grafting of styrene/divinylbenzene (DVB) onto PFA films with thicknesses of 25, 50, and 100 μm followed by sulfonation to introduce sulfonic acid moiety. It was observed that a concentrated chlorosulfonic acid solution and a high reaction temperature are needed to provide sufficient sulfonic acid as the thickness of the PFA films and the content of DVB both increase. The physicochemical properties of the prepared membranes such as water uptake, proton conductivity, methanol permeability, and chemical stability, were also investigated in this study.

A thiol monomer is shown to copolymerize with vinyl ether, allyl, acrylate, methacrylate, and vinylbenzene monomers. These thiol−ene polymerizations are photoinitiated without the use of photoinitiator molecules. It is seen that the polymerization proceeds more readily when initiatorless samples are irradiated with light centered around 254 nm as compared to 365 nm light. To demonstrate resistance to oxygen inhibition, thin polymer films of 3−15 μm are polymerized while exposed to ambient air. Without photoinitiator molecules present, light is attenuated only by the monomer and polymer. This feature leads to greater penetration of ultraviolet light and allows for the polymerization of extremely thick polymers. Thick cures of up to 25 in. are obtained using a thiol−vinyl ether system.