Synthesis and properties of polyoxyethylated amine polyurethane ionomers

Based on polyoxyethylated amines (M_n = 600, 1,200) derived from n-butyl amine and ethylene oxide, 4,4′-diphenylmethane diisocyanate, and different chain extenders, two series of polyether–polyurethane (PU) ionomers with reasonable mechanical properties were synthesized. Chain-extended by 1,4-butanediol and subsequently reacted with 1,3-propane sultone, PU elastomers can be conveniently converted to PU zwitterionomers whose ions are located in polyether soft segments. Chain-extended by N-methyl diethanolamine or sodium-S-1,2-dihydroxypropyl sulfonate along with ionization by 1,3-propane sultone, PU ionomers with ions incorporated into both hard and soft domains can be prepared. Physical properties were studied by means of Fourier transform infrared spectra, differential scanning calorimetry, and uniaxial stress–strain testing. Complex impedance spectra were also measured to estimate solid-state ionic conductivity. The results show that ionization of both hard and soft segments induced a much decreased glass transition temperature and brought higher ionic conductivity at room temperature. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:2179–2185, 1998     

Polyurethane-crosslinked epoxy resins. I. Mechanical behavior

Polyurethane (PU) prepolymers based on poly(butylene adipate) (PBA) and poly(oxytetramethylene) (PTMO) polyols were employed as a crosslinking agent to the diglycidyl ether of bisphenol A (DGEBA). Then the DGEBA was cured with a tertiary amine catalyst to form PU-crosslinked DGEBA. The tensile strength of both the PU(PBA)-crosslinked DGEBA and PU(PTMO)-crosslinked DGEBA systems increased to a maximum value with increasing PU content in the system and then decreased with further increasing PU content. Izod impact property of these PU-crosslinked DGEBA indicated that the PU(PBA)-crosslinked DGEBA had much more significant improvement than the PU(PTMO)-crosslinked DGEBA. On the contrary, the fracture energy (G_{1 C} value) of the resultant PU-crosslinked DGEBA showed that the PU(PTMO)-crosslinked DGEBA had much higher G_{1 C} values than the PU(PBA)-crosslinked DGEBA.     

Properties of polyamic acid ionomers

Polymers containing amic acid units were produced by reacting an oligomer based on polytetramethylene oxide (PTMO) with 1,2,4,5-benzenetetracarboxylic dianhydride (BTDA). Neutralization by a metal salt produced amic acid ionomers. Similar to other ionomer systems, neutralization from the acid to the ionomer led to the formation of a separate ionic phase as determined by dynamic mechanical analysis. Phase separation resulted in a substantial increase in mechanical properties. The effect of neutralization level, cation, soft-segment molecular weight, and soft-segment end group on mechanical and thermal properties was investigated. © 1993 John Wiley & Sons, Inc.     

Novel block ionomers. III. Mechanical and rheological properties

Select rheological (dynamic viscoelastic) and mechanical properties of novel block cationomers and anionomers and their blends have been investigated. The block ionomers were linear di‐ and triblocks, and symmetric three‐arm stars comprising hydrophobic polyisobutylene (PIB) blocks attached to ionized poly(methacrylic acid) (PMAA^?X⁺, where X⁺ = Na⁺, Zn²⁺) and poly[2‐(dimethylamino)ethyl methacrylate] (PDMAEMA⁺I^?) blocks. The specific structures investigated were the well‐defined diblocks PIB‐b‐PMAA^? and PIB‐b‐PDMAEMA⁺ and their blends, the triblocks PMAA^?‐b‐PIB‐b‐PMAA^? and PDMAEMA⁺‐b‐PIB‐b‐PDMAEMA⁺ and their blends, and the three‐arm star anionomer Φ(PIB‐b‐PMAA^?)₃. For comparison, the properties of the precursor PIBs and unionized blocks have also been studied. Hydrogen bonding between the carboxyl groups of the PMAA blocks in PIB‐b‐PMAA diblocks leads to inverse micelles. Neutralization of the PMAA by Zn(AcO)₂ and quaternization of the PDMAEMA segments by CH₃I in the triblock copolymers and star copolymers yielded ionic domains, which self‐assemble and produce physical networks held together by coulumbic interaction. The physical/chemical characteristics of the domains control the viscoelastic behavior and mechanical properties of these block ionomers. The mechanical properties of the various block ionomers were significantly enhanced relative to the precursors, and they were thermally stable below the transition temperature. Further, the thermomechanical properties of these novel materials were satisfactory even above 200°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1516–1525, 2003     

Studies on interpentrating polymer networks of polyurethane and polybismaleimide. I. Polyurethane and bismaleimide-urethane copolymer

The interpenetrating polymer networks (IPNs) of polyurethane (PU) and the mixture of bismaleimide (BMI) and the 2-hydroxylethyl methacrylate (HEMA)-terminated PU prepolymer (HPU) were prepared by using a simultaneous polymerization technique. The effects of the PU molecular weight and the amounts of the PU on the mechanical properties, thermal stability, and dynamic mechanical properties are discussed. The IPNs exhibited superior ultimate tensile strength as the polyol of PU and HPU in the IPNs is based on poly(tetramethylene oxide) (PTMO) glycol of molecular weight 1000 (PTMO1000). Izod impact property of the IPNs indicated that the PU(PTMO1000)/BMI-HPU(PTMO1000) IPNs had much more significant improvement than that of the PU(PTM02000)/BMI-HPU(PTMO2000) IPNs. Better thermal stability was shown by the IPNs as compared with the components of the networks, i.e. PU or BMI-HPU copolymers. The dynamic mechanical analysis (DMA) indicates that these IPNs show various shifts in the loss moduli(E) at the high and low temperature transition peaks for various molecular weight of the polyol employed in the PU. Better compatibility between BMI and PU was found as the PU(PTMO1000) was employed.To whom all correspondence should be addressed.     

Synthesis and characterization of quaternary ammonium ionomers

The cationic monomers, MPDMAC₁₆ and MPDMAC₁₈, were obtained by quaternization of methacrylamidopropyl–N,N′‐dimethylamine with n‐alkyl iodides (1‐iodohexadecane and 1‐iodooctadecane) in ethyl acetate. Hydrophobic ionomers of MPDMAC₁₆ and MPDMAC₁₈ with N‐substituted acrylamides were prepared at 60 ± 0.1°C in DMF using AIBN initiator. The cationic monomers and ionomers were characterized by ¹H‐ and ¹³C‐NMR spectroscopy. The copolymer composition was evaluated from elemental analysis data using carbon/nitrogen (C/N) ratio. The molecular weight distributions of ionomers were obtained from GPC analysis. Both the dilute solution and concentrated solution properties of ionomers were studied by viscometry at 30°C. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1100–1105, 2005     

Synthesis and characterization of side‐chain liquid‐crystalline ionomers containing quaternary ammonium salt groups

A series of thermotropic side‐chain liquid‐crystalline ionomers (LCIs) containing 4‐(4‐alkoxybenzyloxy)‐4′‐allyloxybiphenyl (M) as mesogenic units and allyl triethylammonium bromide (ATAB) as nonmesogenic units were synthesized by graft copolymerization upon polymethylhydrosiloxane. The chemical structures of the polymers were confirmed by IR spectroscopy. DSC was used to measure the thermal properties of these polymers. The mesogenic properties were characterized by polarizing optical microscopy, DSC, and X‐ray diffraction. Homopolymers without ionic groups exhibit smectic and nematic mesophases. The nematic mesophases of the ionomers disappear and the mesomorphic temperature ranges decrease with increasing concentration of ionic units. The influence of the alkoxy chain length on clearing temperature (T_c) values of ionomers clearly shows an odd‐even effect, similar to that of other side‐chain liquid‐crystalline polymers. The mesomorphic temperature ranges increase with increasing alkoxy chain length when the number of alkoxy carbon is over 3. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2879–2886, 2003     

Preparation of poly(IPDI‐PTMO‐siloxanes) and influence of siloxane structure on reactivity and mechanical properties

Siloxane‐modified polyurethanes were prepared through isophorone diisocyanates (IPDI), poly(tetramethylene oxide) (PTMO), and siloxanes. IPDI served as the hard segment in the structure. Both PTMO and siloxanes were diols and served as the soft segments. In addition, different chemical structures of siloxanes were used, in which siloxane chains would remain in the main chain of polyurethanes (PU) or become the side chain of PU. First, the reactivities of PTMO and siloxanes to react with IPDI in bulk system were studied through DSC, in which the reaction heat was related to their reactivities. Copolymerization of IPDI, PTMO, and siloxanes in bulk were also studied. The results showed that hydrophobicity and steric hindrance of siloxane diols led to their low reactivities. Next, a series of siloxane‐modified PU in toluene solvent were synthesized, and the conversion of NCO groups was determined by the method of chemical titration. In the synthesis of PU copolymers in a solution polymerization, because of low reactivity of siloxanes, a two‐step procedure was adopted. The siloxane diol was first reacted with IPDI in toluene to form NCO‐terminated prepolymer. Then PTMO was added to form final PUcopolymers. The addition of side‐chain siloxanes resulted in PU copolymers with higher molecular weight than main‐chain siloxanes. Both main‐chain and side‐chain siloxanes increased the elongation at break and tensile strength of final PU copolymers. The microphase‐separation of siloxane segments was observed by SEM, which was the main cause for the improved mechanical properties. POLYM. ENG. SCI., 47:625–632, 2007. © 2007 Society of Plastics Engineers.     

Mechanical and dynamic properties of graft polyurethane/allyl novolac resin simultaneous interpenetrating network

Two series of polyurethane (PU)/allyl novolac resin simultaneous interpenetra ing networks (SINs) were synthesized. The PU components were prepared by reacting 4,4′-diphenyl methane diisocyanate with poly(tetramethylene oxide) (PTMO), whose molecular weight range was 600–700 (for convenience, this polymer was called UT1), 900–1050 (UT2) and 1900–2100 (UT3), respectively. The phenolic resin component was synthesized by substituting the hydroxy groups of the phenolic resin with the allyl group. To prove that the alkene group can be applied as a binding element between the networks to improve the network compatibility, trimethylol propane monoally ether (TMPME) with a double bond was chosen as the PU chain extender in one series of the PU/allyl novolac resin SINs (designated TUT1, TUT2 and TUT3 for different molecular weights of PTMO used as PU soft segments). After a detailed study of the thermal, mechanical, and dynamic properties and morphology, the extent of phase mixing of the graft PU/allyl novolac resin SINs (TUT series SINs) was significantly improved over that of UT series SINs. This result is consistent with the loss tangent shift in dynamic mechanical analysis measurements and with transmission electron microscope micrographs. The mechanical properties of the graft SINs (TUT series) were lower than those of the original SINs (UT series) because TMPME with bulky structure was used as the chain extender of PU.     

Exploration of the difference of reaction rates for polyester and polyether urethane prepolymers with 3,3′-dichloro-4,4′-diaminodiphenylmethane

Polyester (PEPA) and polyether (PTMO) prepolymers with NCO end groups were synthesized. The chain extension reaction of these prepolymers with MOCA diamine was studied by FTIR spectrometry and found to be a second-order reaction. Data on chain extension reaction rate constants and activation energy showed that the chain extension reaction rate of the PEPA prepolyme with MOCA was faster than that of PTMO prepolymer with MOCA. Such a difference of chain extension reaction rate for PEPA and PTMO prepolymers with MOCA can be explained by hydrogen bonding interaction and miscibility between hard and soft segments in the cast polyurethane elastomer. The hydrogen bonding interactions of MOCA with PEPA prepolymer and PTMO prepolymer without chain extension reaction convincingly demonstrated the difference of chain extension reaction in the polyurethane-urea systems. © 1995 John Wiley & Sons, Inc.     

Influence of ionic groups on the crystallization and melting behavior of segmented polyurethane ionomers

The isothermal crystallization kinetics and melting behavior of the soft segment in polyurethane (PU) ionomer/nonionomer based on PCL‐4000 (poly(ε‐caprolactone)) were investigated using polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). In general, the presence of ionic groups in PU ionomers can promote the formation of a more stable crystalline structure and lower the equilibrium melting temperature of the crystallizable phase. Comparison between the crystallization characteristics of PU nonionomers and ionomers suggests that the Coulombic Forces between ionic groups within hard segment can increase the crystallization rate and decrease the crystal size of soft segment when the total molecular weight (M_w) of PU ionomer is higher than ～71,000. On the other hand, the opposite effect of ionic groups on the crystallization rate is observed in PU ionomers with M_w below ～20,000. The DSC thermograms illustrate that the ionic groups can significantly enhance the microphase separation in PU ionomers with higher M_w values. By the control and manipulation of crystallization and microstructure formation in PU ionomer, it is possible to achieve shape memory PUs with superior physical property. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4603–4613, 2006     

Synthesis, physical properties and enzymatic degradation of poly (oxyethylene-b-butylene succinate) ionomers

A series of poly(oxyethylene-b-butylene succinate) (POBS) ionomers were synthesized by a two-step polycondensation of succinic acid and mixed monomers of sodium sulfonated polyethylene glycol (SPEG) and 1,4-butanediol. The composition and chemical structure of these segmented ionomers were determined by ¹H NMR spectroscopy. To evaluate the potential uses of POBS copolymer in disposable applications, we investigated the crystallinity, dynamic mechanical properties and susceptibility to enzymatic hydrolysis. The crystallinity of POBS copolymer decreased considerably with increasing SPEG content because ionic interaction led to retardation of chain folding. Even so, POBS with 0.5 mol% SPEG showed the highest storage modulus among tested samples. This result is attributed to intermolecular interactions. Enzymatic hydrolysis of POBS copolymer occurs more rapidly than homo poly(butylene succinate) and was drastically accelerated with increasing ionic contents. This is attributed to the presence of the ionic group, which not only reduced the crystallinity but also improved hydrophilicity on the POBS surface.     

Effect of ethylene ionomers on the properties of crosslinked polyethylene

Most premature failure of underground crosslinked polyethylene (XLPE) cables in service, a matter of great concern, is due to aging induced by water treeing. To improve the water‐tree resistance, sodium‐neutralized poly (ethylene‐co‐acrylic acid) (EAA–Na) ionomers were blended with XLPE; the EAA–Na ionomers were prepared through the neutralization of sodium hydroxide and poly(ethylene‐co‐acrylic acid). A series of XLPE/EAA–Na ionomer blends were investigated through the measurement of the water absorption ratio, water treeing, and mechanical and dielectric testing; the results strongly suggested that EAA–Na ionomers could improve the water‐tree resistance of XLPE, and the XLPE/EAA–Na blends retained excellent mechanical properties and dielectric properties. Moreover, through the characterization of XLPE/EAA–Na blends with Fourier transform infrared spectrometry, dynamic mechanical analysis, and scanning electron microscopy, it was found that the neutralization reaction could be achieved completely; the XLPE and EAA–Na ionomers were partially compatible, so the EAA–Na ionomers could be dispersed well in the matrix with the process examined in this study. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3483–3490, 2007     

High styrene–rubber ionomers,an alternative to thermoplastic elastomers

High styrene rubber ionomers were prepared by sulfonating styrene–butadiene rubber of high styrene content (high styrene rubber) in 1,2‐dichloroethane using acetyl sulfate reagent, followed by neutralization of the precursor acids using methanolic zinc acetate. The ionomers were characterized using X‐ray fluorescence spectroscopy, Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), dynamic mechanical analysis (DMA), and also by the evaluation of mechanical properties. The FTIR studies of the ionomer reveal that the sulfonate groups are attached to the benzene ring. The NMR spectra give credence to this observation. Results of DMA show an ionic transition (T_i) in addition to glass–rubber transition (T_g). Incorporation of ionic groups results in improved mechanical properties as well as retention of properties after three cycles of processing. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2294–2300, 2002     

Effects of contact surface area of chains on the mechanical properties of poly(methyl methacrylate-co-acrylate) ionomers

Summary The dynamic mechanical properties of a new ionomer system, poly(methyl methacrylate-co-sodium acrylate), were studied. In addition, to investigate the effect of the chemical structure of ionic group on the mechanical properties, the data obtained from the sodium acrylate ionomers were compared to those obtained from sodium methacrylate ionomers. The matrix and cluster T _gs for the methacrylates were found to be higher than those for the acrylates. It was argued that the difference in the T _gs might be explained with the concept of contact surface area of the chain. Received: 27 November 1998/Revised version: 6 January 1999/Accepted: 13 January 1999     

Effects of the cation valence on the mechanical properties of sulfonated polystyrene ionomers containing dicarboxylate salts

The dynamic mechanical properties of Ba(II)-neutralized poly(styrene-co-styrene sulfonate) ionomers-containing Ba salt of aliphatic diacid were investigated and compared with those of Na(I)-neutralized ionomers-containing Na diacid salt. It was found that the addition of diacid salts led to a negligible change in the matrix and cluster T _gs of the Ba and Na ionomers regardless of the chain length of the aliphatic diacid salts. The log E′ of Ba ionomers, however, increased linearly with increasing chain length of Ba diacid salt, which was different from that of Na ionomers. On increasing wt% of the salts in the ionomers, the matrix T _gs of Ba and Na ionomers did not change, but the cluster T _gs increased slightly for Ba and Na ionomers, except for the Na ionomer-containing C₁₆ diacid salt. In addition, the log E′ increased linearly with the wt% of diacid salts, but the increasing rate was higher for the Ba ionomers, compared to Na ionomers. Thus, it was suggested that the Ba diacid salts would face more difficulty in the formation of multiplet with the ionic groups of the ionomers, compared to Na ionomer system; thus, more Ba diacid salts were phase-separated, which showed a stronger filler effect. In addition, since the Ba ionomers did not flow easily above the cluster T _g of the ionomers, it was proposed that the multiplets of Ba ionomers acted still as effective physical cross-links above cluster T _g, to some extent. Finally, it was concluded that the difference in anionic groups, the increasing amount of Ba salts, and the divalent cation enhanced the filler effects strongly.     

Polyimide‐polyurethane/urea block copolymers for highly sensitive humidity sensor with low hysteresis

Polyimide (PI)‐polyurethane‐urea (PU) block copolymers (PI‐PU75/25, PI‐PU50/50, and PI‐PU25/75) were prepared by reaction between anhydride‐terminated poly(amic acid) prepolymers with various number‐average degree of polymerization = 73/49/25) and isocyanate‐terminated urethane‐urea prepolymers with various (11/21/31) to obtain high performance capacitive humidity sensors. Pure PI and PU were also prepared to compare with PI‐PU copolymers. This study examined the effect of PU content on the water absorption %/water vapor transmission rate, thermal and mechanical properties and sensing properties of PI‐PU block copolymers. The thermal stability and mechanical properties of the copolymer decreased markedly with increasing PU content. The sensitivity of sensor increased sharply with increasing PU content from 0 to 25 wt %, and then increased a little. The hysteresis of sensor decreased sharply with increasing PU content up to 50 wt %, and then decreased a little. These results demonstrate the apparent upside of using two copolymers (PI‐PU75/25 and PI‐PU50/50) compared to using pure PI, in terms of sensor performance. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44973.     

Some properties of styrene‐based ionomers. I

Some properties of styrene‐based ionomers containing alkali metal salts of acrylic acid or methacrylic acid have been investigated. A study has been conducted to examine the influence of the acidic content and nature (acrylic or methacrylic) and the nature of the alkali metal salt on the glass transition temperature, density, melt index and activation energy of a flow of the styrene‐based ionomers. The present studies have indicated that the temperature of glass transition (T_g) of sodium ionomers increases as the sodium content rises and the region of the glass transition broadens. The T_g's of the styrene‐acrylic acid (S‐AA) ionomers do not depend on the nature of the alkali metal introduced into the copolymer. The density of films rises with the content of acid or salt introduced to the polystyrene chain. The melt index of the investigated ionomers depends on the amount and type of the introduced acid and salt as well as on the molecular weight of the initial copolymer. The energy of activation of the flow is independent of the polymer molecular weight; however, the energy of activation of flow of the ionomers increases with larger ionic radii of the introduced alkali metal. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 55–62, 2003     

Melt synthesis of sulfonated EPDM ionomers in batch and continuous processes

Zinc-neutralized sulfonated EPDM ionomers (Zn-SEPDM) were prepared by batch and continuous melt sulfonation processes, and the ionomer products were compared with ionomers synthesized by sulfonation of EPDM in homogeneous solution. The efficiency of a batch melt sulfonation using an intensive mixer as a reactor was comparable to that of the solution sulfonation process, but the efficiency of the melt sulfonation in a twin-screw extruder was considerably lower, which was thought to be a consequence of a relatively short reaction residence time due to limitations of the equipment. Melt neutralization was not complete, which produced a dark colored product. However, the incomplete neutralization and the color of the product did not affect the mechanical properties of the melt sulfonated ionomers, which were comparable to those of ionomers made by conventional solution sulfonation. The metal sulfonate concentration alone determined the mechanical properties of the ionomer. Melt sulfonation of Zn-SEPDM ionomers by batch or continuous melt processes appears to be a practical alternative to solution sulfonation, but further optimization of the melt sulfonation processes is needed to ensure uniform sulfonation and complete neutralization.     

Dual-curing of anionic aqueous-based polyurethanes at ambient temperature

Polyurethane (PU) prepolymers are prepared by a polyaddition of isophorone diisocyanate, polypropylene glycol-1000, and 2,2-dimethylolpropanic acid. The anionic aqueous-based PU dispersions are derived from a water dispersion process of these NCO-terminated PU prepolymers together with a neutralization and a chain extension. They have both terminal amino and pendent carboxylic groups which are potentially reactive sites toward a di-functional epoxy and a tri- or di-aziridinyl compound of a dual-curing PU system, respectively. The stabilities of the resulting PU dispersions on zeta potential and particle size distributions are investigated. The improvements on mechanical, physical, and thermal properties of these dual-cured PU systems are also evaluated. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1661–1671, 1998