Cationic ring-opening polymerization of 2-phenyl-1,3,6,2-trioxaphosphocane

Summary The ring-opening polymerization of 2-phenyl-1,3,-6,2-trioxaphosphocane (4), an eight-membered cyclic phosphonite, has been investigated. Cationic initiators of PhCH₂-Cl and MeOTf gave polymers, whereas anionic and radical initiators did not yield polymer. The structure of polymer was examined by IR, ¹H, ³¹P, and ³¹C NMR spectroscopy of polymers and elemental analysis as well as the alkaline hydrolysis products. The polymer consisted of two different units, i.e., the major part is the normal phosphinate structure 5 and the minor part is the isomerized unit 6 in 7% with PhCH₂Cl initiation and in 34% with MeOTf initiator. The difference in nature of propagating species from these two initiators are discussed in connection with their reactivities.On leave from the Institute of Chemistry, Academia Sinica, Beijing, China     

Cationic ring-opening polymerization of spirophosphorane, 5-phenyl-1,4,6,9-tetraoxa-5-phosphaspiro[4,4]nonane

Summary This paper reports new cationic ring-opening polymerization of a spirophosphorane, 5-phenyl-1, 4, 6, 9-tetraoxa-5-phosphaspiro (4, 4) nonane, 1. The polymerization of 1. was induced by cationic initiators such as methyl trifluoromethanesulfonate (MeOTf), BF₃·OEt₂, and Et₃O⁺-BF₄ ^– to give polymer 2 consisting of two different units, 2a and 2b. During the reaction cyclic phosphonate 3 and 1,4-dioxane were simultaneously produced. The formation of unit 2b is considered to be due mainly to the cationic ring-opening polymerization of 3.     

Anionic ring-opening polymerization of 2-phenyl-1,3,4-oxadiazolin-5-one and conversion of the resulting polymer,N-benzamido-1-nylon,to N-amino-1-nylon

Summary The ring-opening polymerization of 2-phenyl-1,3,4-oxadiazolin-5-one (1) was carried out anionically both in bulk and in DMF solution at 140°C for 15 h in the presence of various initiators, such as alkaline metal salts of 1, alkaline metal fluorides and tertiary amines, leading to N-benzamido-l-nylon (2) having Mns up to 2,000. Hydrolysis of the pendant benzamido groups of the resulting polymer was successfully achieved in aqueous ethanol containing concentrated hydrochloric acid at 100°C to give N-amino-l-nylon (3). The original polymer dissolves easily in aliphatic and aromatic alcohols and polar aprotic solvents, whereas the hydrolyzed polymer is not soluble in these solvents but highly soluble in water. In dilute aqueous solutions, the latter polymer behaves as common polyelectrolytes with flexible backbone. Polymers 2 and 3 began to lose weight in air at around 200 and 170°C, respectively.     

Polymerization of vinyl chloride with butyllithiums and metallocene catalysts

Polymerizations of vinyl chloride (VC) with butyllithium (BuLi) and metallocene catalysts were investigated. In the polymerization of VC with BuLi, the activity for polymerization decreased in the following order; t‐BuLi > n‐BuLi > s‐BuLi. A polymer controlled structurally in the main chain was found to be synthesized from the polymerization of VC with BuLi. The molecular weights of polymers obtained in bulk polymerization were higher than those of polymers obtained in solution. A linear relationship of the M_n of the polymer and the polymer yields was observed. The M_w/M_n of the polymer did not change significantly during polymerization, although the M_w/M_n was around 2. Thermal stability of the polymer obtained with BuLi was higher than that of polymer obtained with radical initiators, as determined by TGA measurements. In the polymerization of VC with Cp*TiX₃/MAO (X: Cl and OCH₃) catalysts, polymers were obtained with both catalysts, although the rate of polymerization was slow. The Cp*Ti(OCH₃)₃//MAO catalyst in CH₂Cl₂ gave higher‐molecular‐weight polymers in a better yield than in toluene. From elemental analysis and the NMR spectra of the polymers, the Cp*Ti(OCH₃)₃/MAO catalyst gave polymers consisting of repeating regular head‐to‐tail units, in contrast to the Cp*TiCl₃/MAO catalyst, which gave polymers having anomalous units.     

Polymerization of [2,5-bis(trifluoromethyl)phenyl]acetylene and polymer properties

Summary [2,5-Bis(trifluoromethyl)phenyl]acetylene [BTFPA; HCCC₆H₃-2, 5-(CF₃)₂]polymerized with W, Mo, and Nb catalysts to produce methanol-insoluble polymers in high yields. The poly(BTFPA) produced by the W(CO)₆-based catalyst at 30 °C was soluble in p-(CF₃)₂C₆H₄, and had relatively high molecular weight ([]=0.352 dL/g in p-(CF₃)₂C₆H₄). The main chain of the polymer was composed of alternating double bonds, and the polymer was a dark brown solid. The temperature at which the weight loss of the polymer started was higher than 300 °C. The polymerization behavior and polymer properties for BTFPA are compared with those for phenylacetylene and [o-(trifluoromethyl)phenyl]acetylene.     

Synthesis and polymerization of p-bromomethylstyrene and p-lodomethylstyrene

Summary Synthesis of p-bromomethylstyrene (3) and p-iodome-thylstyrene (4) is reported. 3 was obtained by the bromomethylation of 2-phenylethyl bromide followed by dehydrobromination of the resultant p-(2-bromoethyl) benzyl bromide (2) with t-BuOK, as well as by cleaving p-vinyl-benzyl methanosulfonate with LiBr in the presence of 18--crown-6. 4 was obtained from p-chloromethylstyrene (1) via the Finkelstein reaction. 3 was polymerized successfully in the presence of free-radical initiators, but 4 was found to be too unstable to give a well-defined polymer.     

Investigations on the role of acyl initiators and CO2 in nylon 4 polymerization

Summary The preparation of high molecular weight nylon 4 with alkali metal pyrrolidonate catalysts, acyl initiators, and CO₂ was studied. Isolated sodium pyrrolidonate and the appropriate amount of acyl initiator gave unusually high molecular weight nylon 4 (m_w >200,000). The molecular weight-initiator concentration relationship indicates that acyl compounds play a dual role in the polymerization, acting both as initiators and scavengers for chain-terminating impurities. One potential chain terminator was identified as 4-aminobutyric acid. The high polymer molecular weights obtained in the presence of CO₂ can also be explained by the scavenging of chain terminators by CO₂. Determination of the number of growing chains, however, shows that CO₂, unlike the acyl compounds, is not an initiator in nylon 4 polymerization.Presented at the 1984 International Congress of Pacific Basin Societies, Honolulu, Hawaii, December 1984     

Molecular engineering of liquid crystalline polymers by living polymerization

Summary This paper describes the synthesis and characterization of poly{3-[4-cyano-4-biphenyl)oxy]propyl vinyl ether} [poly(6-3)] macromonomers obtained by the functionalization of the growing chain end of the corresponding living polymer obtained by the initiation of the cationic polymerization of 3-[4-cyano-4-biphenyl)oxy]propyl vinyl ether with CF₃SO₃H/S(CH₃)₂, with 2-hydroxy ethyl methacrylate [poly(6-3)-I], 2-[2-(2-allyloxyethoxy)ethoxy]ethanol [poly(6-3)-II] and 10-undecen-1-ol [poly(6-3)-III].Part 20: V. Percec and M. Lee, J. Mater. Chem., submitted     

Asymmetric polymerization of diphenyl-2-pyridylmethyl methacrylate leading to optically active polymer with high one-handed helicity

Summary Diphenyl-2-pyridylmethyl methacrylate (D2PyMA) was polymerized with organolithium complexes of four novel chiral ligands (1–4) which were prepared from (+)-tartaric acid. The complexes of 3 and 4 gave the optically active poly (D2PyMA) with a highly one-handed helical structure. The fractionation of the polymer afforded the poly (D2PyMA) with almost pure one-handed helicity ([] ₃₆₅ ²⁵ -1400^°) in good yield.These chiral lithium complexes were not effective for the asymmetric polymerization of triphenylmethyl methacrylate.     

Preparation of poly(methyl methacrylate) by ATRP using initiators for continuous activator regeneration (ICAR) in ionic liquid/microemulsions

In this study, we reported the synthesis of poly(methyl methacrylate) (PMMA) polymers via initiators for continuous activator regeneration atom transfer radical polymerization using CCl₄ as initiator, FeCl₃·6H₂O/hexamethylene tetramine as catalyst complex, and 2,2′-azobis(isobutyronitrile) (AIBN) as reducing agent. The polymerization was conducted at 60 °C in the ionic liquid based microemulsion with hexadecyl trimethyl ammonium bromide (CTAB) as surfactant. Kinetics experimental results showed that the polymerization proceeded in a controlled/‘living’ process. The effects of the molar ratio of [CCl₄]/[FeCl₃·6H₂O], the concentration of AIBN, temperature and the concentration of CTAB on the polymerization was investigated. The effect of CTAB concentration on the resulting PMMA particle size was also investigated. The obtained polymer was characterized by proton nuclear magnetic resonance and gel permeation chromatography. The living characteristics were demonstrated by chain extension experiment.     

Syntheses of AB2 3- and AB4 5-miktoarm star copolymers by combination of the anionic ring-opening polymerization of hexamethylcyclotrisiloxane and nitroxide-mediated radical polymerization of styrene

AB₂ 3- and AB₄ 5-miktoarm star copolymers were prepared by combination of the anionic ring-opening polymerization (AROP) of hexamethylcyclotrisiloxane (D₃) and the TEMPO-mediated radical polymerization of styrene (St). Initially, two kinds of dendritic multifunctional initiators were prepared. One has a 4-bromobutoxy group and two TEMPO-based alkoxyamines and the other has a 4-bromobutoxy group and four TEMPO-based alkoxyamines. Treatment of the multifunctional initiators with tert-butyllithium gave the corresponding lithiobutoxy derivatives, and AROP of D₃ by the lithiobutoxy derivatives gave poly(D₃) with M_w/M_n of 1.07-1.12. Nitroxide-mediated radical polymerization of St by the poly(D₃)s at 120 °C gave AB₂ 3- and AB₄ 5-miktoarm star copolymers with M_w/M_n of 1.15-1.28. Their structures were analyzed by means of ¹H NMR and SEC measurements.     

Anti-bredt monomers

Summary 1-Aza-6-oxabicyclo [3.2.1]octan-7-one 3 polymerized in bulk to polyurethane at 112–131°C with opening of the 5-membered urethane ring. Organometallic, cationic, anionic and organophosphoric initiators polymerized the strained bicyclic urethane to the polyurethane. In solution the monomer was shown to polymerize slowly under the influence of phosphoric acid. The driving force for the polymerization may be the relief of strain energy in the monomer caused by a boat conformation of the 6-membered ring.     

Anionic polymerization of fluorine-containing vinyl monomers

Summary The anionic polymerization of pentafluorophenylmethyl methacrylate (PFPMA) were examined with several anionic initiators. The initiators of relatively low activity such as t-C₄H₉OK, organozinc compounds and Al(C₂H₅)₃ produced poly(PFPMA) in fairly high yields though no polymer was obtained by the initiations of n-C₄H₉Li and C₂H₅MgBr within 7 days. The anionic polymerization reactivity of PFPMA was found to be strongly affected by the pentafluorophenyl group though the e-value of PFPMA is similar to those of methyl methacrylate and benzyl methacrylate.Part 7, Polym. J. 19, 958 (1987)     

Morphology of latex particles formed by poly(methyl methacrylate)-seeded emulsion polymerization of styrene

Poly(methyl methacrylate)–polystyrene composite particle latexes were prepared by poly(methyl methacrylate)-seeded emulsion polymerization of styrene employing batch, swelling-batch, and semibatch methods. The changes in particle morphology taking place during the polymerization reaction were followed by electron microscopy. Anchoring effect exerted by ionic terminal groups introduced by ionic initiator was found to be the main factor in controlling the particle morphology. The polymer particles obtained by oil-soluble hydrophobic initiators such as azobisisobutyronitrile and 4,4′-azobis-(4-cyanovaleric acid) gave the inverted core-shell morphology. Water-soluble hydrophilic initiator, K₂S₂O₈, also gave the inverted core-shell morphology. However, in this case the occurrence of the halfmoonlike, the sandwichlike, and the core-shell morphologies were also observed depending upon the polymerization conditions. The distribution of terminal ? SO groups on the surface area of polystyrene particles could be controlled by initiator concentration and polymerization temperature. Viscosity of polymerization loci dictated the movement of polymer molecules, thus causing the unevenness of particle shape and phase separation at high viscosity state. Viscosity was controlled by the styrene/poly(methyl methacrylate) ratio, the addition of a chain transfer agent or a solvent which is common to polystyrene and poly(methyl methacrylate).     

Polymerization via zwitterion 27. No-catalyst copolymerization of 2-phenyl-1,3,2-dioxaphospholane with β-hydroxyalkyl acrylates and methacrylates

Summary This paper describes No-Catalyst Copolymerizations between ethylene phenylphosphonite (EPO) as M_N and four -hydroxyalkyl acrylates and methacrylates as M_E. In all combinations polyphosphinate type copolymers were obtained above 130 °C without added catalyst. The first step of reaction was a proton-transfer step to yield a transient phosphonium-alkoxide zwitterion 5 and generated a phosphorane intermediate like 6. The subsequent reactions of 6 were rather complicated. It was possible to conceive several zwitterions to lead to polymer units. The liberation of ethylene oxide and/or propylene oxide was observed as a side reaction during polymerization.Dedicated to the 60th birthday of Professor C. I. Simionescu     

Hybrid copolymerization of alkyl vinyl ethers with glycidyl ethers

Homopolymerization and copolymerization experiments of isobutyl and dodecyl vinyl ether with propylene oxide, and some glycidyl ethers have been carried out by using both conventional cationic initiators (BF₃, BF₃·OEt₂) and 4-chlorophenyldiazonium tetrafluoborate as cationic photoinitiator. Conventional polymerization experiments performed under vacuum at low and room temperature gave rise to a mixture of the two homopolymers, indicating that the epoxide and vinyl ethers are incompatible with respect to chemical reactivity and that apparently no hybrid copolymerization occurs. Analogous results were obtained in parallel photoinitiated polymerization experiments.     

Neutral Pd(II) and Ni(II) Acetylide Catalysts for the Polymerization of Methyl Methacrylate

Homogenous polymerization of methyl methacrylate using Pd(II)- and Ni(II)-based acetylide complexes as initiators has been investigated. M(PR'₃)₂(CCR)₂ (M=Pd, Ni; R'=PPh₃, Pn-Bu₃; R=Ph, CH₂OH, CH₂OOCCH₃, CH₂OOCPh, CH₂OOCPhOH-o) were found to be a novel type of effective initiators for the polymerization of methyl methacrylate. Among them, Pd(C CPh)₂(PPh₃)₂ (PPP) shows the highest activity in the MMA polymerization and the PMMA obtained is a syndiotactic polymer with high number-average molecular weight (M _n) of 14.1 × 10⁴. Some features and kinetic behavior of MMA polymerization initiated by PPP were studied in detail. The polymerization reaction is first-order with respect to both [PPP] and [MMA]. Radical polymerization mechanism is proposed.     

Polymerization of allyl methacrylate with wool fabric using different initiators

Polymerization of allyl methacrylate (AMA) with wool fabrics using different initiators, namely, potassium persulphate, Fe²⁺? H₂O₂, benzoyl peroxide, ceric ammonium nitrate, and vanadium pentanitrate, was investigated. The percent of polymer add-on depends upon the type and concentration of the initiator. Addition of metallic salts such as Fe³⁺ to the polymerization system enhances polymerization significantly when benzoyl peroxide and potassium persulphate are used independently as initiator. The opposite holds true for ceric ammonium nitrate and vanadium pentanitrate. With Fe²⁺? H₂O₂, on the other hand, the enhancement is marginal. Also studied was the incorporation of Li⁺, Cu⁺⁺, and Fe³⁺ at different concentrations in AMA—wool–benzoyl peroxide polymerization systems. Determination of the polymer add-on on the basis of double bond analysis revealed that the remained double bond is governed by the magnitude of the polymer add-on as well as by the type of initiator.     

Living carbocationic polymerization

Summary The effect of polymer precipitation that occurs during polymerization on the number average molecular weight ¯M_n has been investigated in conjunction with the recently described trans-2,5-diacetoxy-2,5-dimethyl-3-hexene (DiAcODMH₆)/BCl₃/isobutylene(IB)/CH₃Cl/- 35° system using both the IMA and AMI techniques. All the experimental data could be described by a common rectilinear l/¯M_n versus l/W_p (W_p = weight of polymer) plot exhibiting an intercept l/¯M_n,max. A simple equation has been derived that explains quantitatively the results and suggests that product molecular weights obtained in heterogeneous polymerizations are determined by polymer precipitation which in turn leads to chain transfer. An Arrhenius analysis of ¯M_n,max values obtained at various temperatures corroborates this proposition and suggests polymer precipitation to control ¯M_n. That precipitation conditions determine ¯M_n seem also to hold true for conventional AlCl₃-induced IB polymerizations.Papers XXI of this series will appear in Polymer Preprints, R. Faust and J.P. Kennedy, 29(2), 1988     

Synthesis and radical polymerization of 1,1,2-tricyano-2-carbomethoxycyclopropylstyrene

Summary An isomeric mixture (meta-and para-) of 1,1,2-tricyano-2-carbomethoxycyclopropylstyrene 3 was prepared by cyclopropane formation from bromomalononitrile and methyl styrylidenecyanoacetate 2. The substituted styrene monomer 3 was polymerized with free radical initiators to obtain the polymers with multicyano functions in the pendant group. The resulting polymers were soluble in acetone and the inherent viscosities were in the range of 0.20–0.28 dL/g. Solution-cast films were clear and brittle with a T_g of 102°C.