Side chain acrylic

Copolymers of acrylic acid and long side chain acrylic esters and [107]... 

TPAs bearing cross-linkable oxetane functionalities (52) (Scheme 3.20) has been developed [95,96], This material can be easily photo-patterned by exposure to a very short wavelength UV light source to form a patterned and insoluble HTL. Similar photo-cross-linkable HTMs based on side-chain acrylate or styryl functional groups have been synthesized (53,54) [97]. A series of spiro-linked and photo-cross-linkable HTMs have been patented by the Canon group [98]. 

FIGURE 25 Piezoelectric coefficient, for a side-chain acrylic FLCP on heating, versus temperature [30],... 

LCEs forming nematic, cholesteric, and smectic phases have been synthesized, with various chemical structures comprising of both side-chain and main-chain types. Because of the multitudes of preparation techniques, I will here focus on our synthetic methods [7]. Reactive cyanobiphenyl monoacrylate mesogens were mixed with diacrylate cross-linkers to produce a photoinitiated side-chain acrylate NE (Fig. 10.2). As it will be described later, the LCE fixes the liquid crystal orientation at the time of cross-linking, and it can be said that this orientation... 

Mechanical and Thermal Properties. The first member of the acrylate series, poly(methyl acrylate), has fltde or no tack at room temperature it is a tough, mbbery, and moderately hard polymer. Poly(ethyl acrylate) is more mbberflke, considerably softer, and more extensible. Poly(butyl acrylate) is softer stiU, and much tackier. This information is quantitatively summarized in Table 2 (41). In the alkyl acrylate series, the softness increases through n-octy acrylate. As the chain length is increased beyond n-octy side-chain crystallization occurs and the materials become brittle (42) poly( -hexadecyl acrylate) is hard and waxlike at room temperature but is soft and tacky above its softening point. 

An extensive investigation of the dilute solution properties of several acrylate copolymers has been reported (80). The behavior is typical of flexible-backbone vinyl polymers. The length of the acrylate ester side chain has Httle effect on properties. 

Fig. 1. T vs 8 for poly(alkyl acrylates). = number of C atoms in alkyl side chain. To convert MPa to (cal/cm ), divide by 2.05.

To improve the performance of acryUc elastomers, side chains are required where the 5 value is higher than with alkyl groups. Thus the use of polar groups, for instance heteroatoms, is suggested. The general formula for these acrylate monomers may be portrayed as follows ... 

Whilst increasing the length of alkyl side chain can, to some extent, depress Tg and improve low-temperature properties this is at the expense of oil resistance. On the other hand lengthening of the side chain by incorporation of an —O— or an —S— linkage could often depress Tg and reduce swelling in hydrocarbon oils. This led to the commercial development of copolymers of either ethyl or butyl acrylate with an alkoxy acrylate comprising some 20-50% of the total composition. Typical of such alkoxy compounds are methoxyethyl acrylate (1) and ethoxyethyl acrylate (11) ... 

A large number of organic acrylic ester polymer have been prepared in the laboratory. Poly (methyl acrylate) is tough, leathery and flexible. With increase in chain length there is a drop in the brittle point but this reaches a minimum with poly-(n-octyl acrylate) (see Figure 15.12.). The increase in brittle point with the higher acrylates, which is similar to that observed with the poly-a-olefins and the poly(alkyl methacrylate)s, is due to side-chain crystallisation. 

In 1950, Dahlquist et al. [82] reported the use of polyvinyl A -alkyl carbamates as PSA release materials. Since then, many other types of alkyl side chain polymers have been patented for use as release coatings, including copolymers based on higher alkyl acrylates or methaci ylates [83-86], polyvinyl esters of higher aliphatic fatty acids [87], higher alkyl vinyl esters or ethers and a maleic... 

Pittman and Ludwig [115] studied the wetting properties of a series of flu-oroalkyl acrylates having -CH2(CF2) CF2H side chains, where n was 1, 3. 5, 7, or 9. The acrylates with n = 1 and 9 were partially crystalline (attributed to packing of the fluorochemical side chains) with melting points of about 56°C and... 

Polyalkylene oxides (PAO) are prone to chain transfer. This tendency was used by Union Carbide to graft acrylate side chains via UV exposure of a PAO/acrylic monomer(carbamyloxy alkyl acrylate)/photoinitiator blend [58]. The final product was a water-sensitive PSA. 

Two-step 1,4 cycloaddition of enamines, such as was observed with methyl vinyl ketone, is not possible with acrylate or maleate esters. This is due to the fact that, following the initial simple substitution, no side-chain carbanion is available for nueleophilic attack on the a carbon of the iminium ion. Likewise two-step 1,3 eycloaddition, such as that found when alicyclic enamines were treated with acrolein, is impossible with acrylate or maleate esters because transfer of the amine moiety from the original enamine to the side chain to form a new enamine just prior to the final cyclization step is not possible. That is, the reaction between a seeondary amine and an ester does not produce an enamine. 

PSt or PMMA, respectively, was coupled with polymethacrylate having a PEG side chain or methylammo-niumchloride side chain to prepare a block copolymer for giving a hydrophilic surface [55]. Also, PSt-b-PVP [36,37], PSt-b-(hydrophilic vinyl copolymer) [56], PSt-b-po y(sodium acrylate) (PNaA) [57], and PSt-b-PNaA-b-(polyperfluoroacrylate) (PFA) [58] were synthesized for the same application. 

The transformation of the porphyrin intermediate 4 into a chlorin can be achieved after introduction of a C — C double bond into the 15-propanoate side chain of 4 to yield 5. The cyclization of 5 with participation of the 15-acrylic ester side chain under acidic conditions gives the chlorin 6 which is then transformed in a multistep reaction sequence into chlorophyll a. The driving force of chlorin formation from the porphyrin is believed to be the relief of steric strain at the sterically overcrowded porphyrin periphery which gives the desired trans arrangement of the propanoate side chain and the methyl group in the reduced ring. The total... 

Liquid crystalline elastomers (LCEs) are composite systems where side chains of a crystalline polymer are cross-linked. Their mesogenic domains can be ordered nematically and undergo a phase transition to a disordered state at a temperature well above the glass-transition temperamre (Tg) of the polymer. Although the phase transition is thermally driven, LCEs demonstrate electrical conductivity and thus can be electrically stimulated." Ratna" has reported contractions of nearly 30% due to the phase transition of acrylate-based LCEs. 

Many synthetic water-soluble polymers are easily analyzed by GPC. These include polyacrylamide,130 sodium poly(styrenesulfonate),131 and poly (2-vinyl pyridine).132 An important issue in aqueous GPC of synthetic polymers is the effect of solvent conditions on hydrodynamic volume and therefore retention. Ion inclusion and ion exclusion effects may also be important. In one interesting case, samples of polyacrylamide in which the amide side chain was partially hydrolyzed to generate a random copolymer of acrylic acid and acrylamide exhibited pH-dependent GPC fractionation.130 At a pH so low that the side chain would be expected to be protonated, hydrolyzed samples eluted later than untreated samples, perhaps suggesting intramolecular hydrogen bonding. At neutral pH, the hydrolyzed samples eluted earlier than untreated samples, an effect that was ascribed to enlargement... 

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