Poly 2,3-bicyclo hept-2-enes

Polyampholytes, MA copolymers, 284, 336 Poly(anethole-alt-MA), 375, 412, 413, 416, 417 Polyarylates, MA crosslinked, 516 Poly(benzofuran-alt-MA), 320, 324, 386, 387, 414 Poly(l-benzothiophene-alt-MA), 386. 387, 394 Poly(benzyl vinyl ether-alt-MA), 316, 621 Poly(benzyl-o-vinyl formal-alt-MA), 328 Poly(bicyclo[2.2. l]-hepta-2-ene-alt-MA), 350, 586 Poly(bicyclo[2.2. l]hept-5-ene-2,3-dicarboxylic anhydride, 353, 660... 

We have reported the first example of a ring-opening metathesis polymerization in C02 [144,145]. In this work, bicyclo[2.2.1]hept-2-ene (norbornene) was polymerized in C02 and C02/methanol mixtures using a Ru(H20)6(tos)2 initiator (see Scheme 6). These reactions were carried out at 65 °C and pressure was varied from 60 to 345 bar they resulted in poly(norbornene) with similar conversions and molecular weights as those obtained in other solvent systems. JH NMR spectroscopy of the poly(norbornene) showed that the product from a polymerization in pure methanol had the same structure as the product from the polymerization in pure C02. More interestingly, it was shown that the cis/trans ratio of the polymer microstructure can be controlled by the addition of a methanol cosolvent to the polymerization medium (see Fig. 12). The poly(norbornene) prepared in pure methanol or in methanol/C02 mixtures had a very high trans-vinylene content, while the polymer prepared in pure C02 had very high ds-vinylene content. These results can be explained by the solvent effects on relative populations of the two different possible metal... 

The polymerisation of norbornene showed features of a living process when [Pd(RCN)4][BF4]2 complexes were used as catalysts. Poly(2,3-bicyclo[2.2.1]-hept-2-ene)s of high molecular weight (in the approximate range 10 x 103—100 x 103) with small polydispersities (Mw/Mn<1.10), characterised by a relatively high glass transition temperature (Tg = 300 °Q, could be obtained when a solvent mixture of chlorobenzene and nitrobenzene was used at a reaction temperature of 0 °C [10],... 

It is worth noting that catalysts based on simple Co salts are also effective in polymerising norbornene to poly(2,3-bicyclo[2.2.1]hept-2-ene)s interestingly, the polymers exhibited a very high molecular weight (Mw > 1600 x 103) and glass transition temperature (Tg = 380 °C) while being readily soluble in simple hydrocarbons such as cyclohexane [26],... 

Decomposition of the Pd M P species via /1-hydrogen elimination is unfavourable, since both /1-hydrogen atoms, H3 and Hi, are not easily accessible for a Pd-H bond forming process. The suppression of /1-hydrogen abstraction is a prerequisite for the monomer undergoing m-insertion polymerisation, leading, in this case, to poly(2,3-bicyclo[2.2.1]hept-2-ene) [10]. 

Thus, until the last decade, three families of catalysts have been reported to catalyze the addition, or vinyl-type homopolymerization of norbornene resulting in poly(2,3-bicyclo[2.2.1]hept-2-ene). These three catalyst types are the classical TiC -based Ziegler systems (type 1), the zirconocene/aluminoxane systems (type 2) and certain electrophilic palladium(II) complexes (type 3). 

Infrared spectroscopy provides a convenient method for studying the deprotection kinetics of resist polymers. For example, the deprotection kinetics of some alicyclic polymer resist systems comprising (i) poly(methylpropyl bicyclo[2.2.1]-hept-5-ene-2-carboxylate-co-bicyclo[2.2.1]hept-5-ene-2-carboxylic acid) (trivial name poly(carbo-t-butoxynorbomene-co-norbornene carboxylic acid) [poly(CBN-co-NBCA)] (I) and (ii) poly(methylpropyl bicyclo[2.2.1]hept-5-ene-2-carboxylate-co-maleic anhydride) (trivial name poly(carbo-t-butoxynorbomene-co-maleic anhydride) [poly(CBN-aZr-MAH)] (11) and containing triphenylsulfonium... 

Figure 9. Dependence of the glass ( , O) and nematic-isotropic ( , O) phase transition temperatures of (a) poly 5- [6 [4"-(4" -methoxyphenyl)phenoxy]hexyl]carbonyl)bicyclo[2.2.i]hept-2-ene [22] and (b) poly 5-[[[2, 5 -bis[(4"-methoxybenzoyl)oxy]benzyl]oxy]carbonyl]bicyclo[2.2.1]hept-2-ene [182] as a function of the number average degree of polymerization ( , ) and the inverse number average degree of polymerization (O, ). Infinite molecular weight transitions (a) G 41 N 95 I (b) G 99 N 167 I.

The thermotropic behavior of liquid crystalline polynorbornenes also reach their limiting values at 50 repeat units or less [22, 182, 188-190]. For example, Fig. 9 demonstrates that the glass and nematic-isotropic transitions of both terminally and laterally attached systems level off at 25-50 repeat units, and correspond to the transition temperatures of the infinite molecular weight polymers. The same is true of the crystalline melting and smectic-isotropic transition temperatures of poly ( )-endo, exo-5,6-di [ -[4 -(4"-methoxyphenyl)-phenoxy]hexyl]carbonyl bicyclo[2.2.1]-hept-2-ene) [190]. 

Figure 14. Transition temperatures of polyl( )-endo,exo-5,6-di [n-[4 -(4"-cyanophenyl)phenoxy]alkyl]carbo-nyl bicyclo[2.2.1]hept-2-ene s ( >P =41 -266, pdi= 1.21 -1.60) [191], poly 5- [n-[4 -(4"-cyanophenyl)phen-oxy]alkyl]carbonyl bicyclo[2.2.1]hept-2-ene s (DP =43 -290, pdi = 1.08-1.27) [189] andpoly(n-[(4 -(4"-cya-nophenyl)phenoxy)alkyl]vinyl ethers (,DP = 17-32, pdi= 1.09-1.21) [122-127, 212, 213] as a function of the number of methylenic units in their -alkyl spacers from the glassy ( ), crystalline (O), SmC ( ), SmA ( ) and nematic (A) states.

Table 8. Normalized [232] changes in enthalpy and entropy of isotropization per methylenic unit in the spacer of poly ( )-endo,exo-5,6-di [n-[4 -(4"-cyanopheny l)phenoxy ] alkyI]carbonyl) bicyclo[2.2.1 ]hept-2-ene s...

Comparison of the phase diagrams plotted in Fig. 14 of poly(5- [ -[4 -4"-cyano-phenyl)phenoxy]alkyl]carbonyl]bicy-clo[2.2.1]hept-2-ene]s [189] and poly(n-[(4 -(4"-cyanophenyl)phenoxy)alkyl]vinyl ethers [122-127, 212, 213] which contain a single mesogen per repeat unit demonstrates that the glass transition temperature decreases as the flexibility of the polymer backbone increases from polynorbornene to poly(vinyl ether), whereas the isotropiza-tion temperature increases. In addition to revealing additional mesophases at lower temperatures, this increase in polymer flexibility enables the poly(vinyl ether)s to form more ordered mesophases. That is, poly(5- [ -[4 -(4"-cyanophenyl)phenoxy]al-kyl]carbonyl ]bicyclo[2.2.1 ]-hept-2-ene ]... 

Figure 18. Transition temperatures from the glass ( ), crystalline (o), nematic (A) and smectic ( ) phases of poly 5- [n-[4"-(4" -nitrostilbeneoxy)alkyl]carbonyl )bicyclo[2.2. l]hept-2-ene)s (DP =27-42, pdi= 1.08-1.11) [187], 4-n-alkoxy-4 -nitro(stilbene) [228] and poly[3-[(( -(4 -(4"-nitrostilbeneoxy)alkyl)carbonyl)methylene-oxy)methyl]cyclobutene s (DP =61 -72, pdi= 1.14-1.16) [187] as a function of the number of methylenic carbons in their n-alkyl spacers.

Table 21. Thermotropic behavior of poly 5-[[[2, 5 -bis[(4"-n-((perfluoro-alkyl)alkoxy)benzoyl)oxy]benzyl]oxy]carbonyl]bicyclo[2.2.l]-hept-2-ene)s [195],...

This paper describes the synthesis, characterization and application of poly(7-oxa bicyclo[2.2.1]hept-5-ene-2,3-diacetate) (PI )a precursor for polyffurylene vinylene). 

In a similar approach, a new functional monomer 5-(methyl methacryloyl isocyanate)bicyclo[2.2.1]hept-2-ene was recently metathesised using RuCl2-(=CHPh)(PCy3)2 as the catalyst (Scheme 10) [24]. The incorporation of the resulting polymer into poly(methyl methacrylate) produced crosslinked materials which -as expected from the previous results (Schemes 8 and 9) [23] - also had higher thermal stability and solvent resistance than pure PMMA. 

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