Poly-n-alkyl acrylates

S. Matsui and D.R. Paul, Pervaporation Separation of Aromatic/Aliphatic Hydrocarbons by a Series of Ionically Crosslinked Poly(n-alkyl acrylate) Membranes, J. Membr. Sci. 213, 67 (2003). 

Type B. This type of molecular motion involves the rotation of a whole side group, e.g. the n-alkyl ester group in poly (n-alkyl methacrylates) and poly (n-alkyl acrylates). It does not necessarily mean that a complete rotation is made. Moreover a cooperative motion of the backbone might be required for this partly rotation. 

It is apparent that our concepts of the relaxational processes in well studied systems such as the poly(n-alkyl acrylates) and poly(n-alkyl methacrylates) warrant further study and that... 

Matsui and Paul (2003) separated aromatic-aliphatic hydrocarbons by a series of ionically cross-linked poly(n-alkyl acrylate) membranes using a PV technique. 

Three poly(n-alkyl acrylates) PA-H, PA-16, PA-18 and two poly-(vinyl alcohol aliphatic acid esters) PVA-1A and PVA-16 have been synthesized. They are white crystalline polymers at room temperature, characterized with IR, DSC, SALLS-photometer and polarizing microscope. Only PA-I4 and PVA-IZf are effective for 0/ diesel oil. The influences of molecular weight, molecular weight distribution and amount of addition of PA-1i+ and PVA-lif upon the pour-point depression of oil are very alike. These results reveal the length of n-alkyl side-chain of the polyesters plays the most important role in depressing the pour-point of petrolic oil and the order of linking in the ester group seems in no relation to this effect. 

Although poly(n-alkyl acrylates)(PA-esters) with long side-chain have been used early as depressant for pour-point of petrolic oil(1), no studies have been reported on the poly-(vinyl alcohol aliphatic acid esters)(PVA-esters) in this application. We suppose there would exist such possibility as the structures of PA-esters and PVA-esters are very similar to each other except that their forms of ester linking are in reverse order. Therefore it is valuable to investigate the structural features of PA-esters and PVA-esters, and their effects on pour-point depression of oil, not only for scientific interest but also for practical use. 

FIGURE 1.9 Brittle points of poly(n-alkyl acrylate)s and poly(n-alkyl methacrylate)s. (After Rehberg, C. E. and Fisher, C. H. 1948. Ind. Eng. Chem., 40, 1431.)... 

The presence of long side (usually aliphatic) branches in each monomeric unit is a distinctive feature of the structure of the macromolecules of combshaped polymers (cf. Fig. 6.1b). Many higher homologs of poly-n-alkyl acrylates, poly-n-alkyl methacrylates, poly-n-alkylvinyl ethers and esters, poly-n-alkylstyrenes, etc., are among such polymers. 

Fig. 6.1 Brittle points of poly(n-alkyl acrylate)s and poly(n-alkyl methacrylate)s [2].

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. 

ARGET ATRP has been successfully applied for polymerization of methyl methacrylate, ft-butyl acrylate and styrene in the presence of Sn(EH)2 (10 mol% vs. alkyl halide initiator or 0.07 mol% vs. monomer) [164,165]. For all monomers, polymerizations were well controlled using between 10 and 50 ppm of copper complexes with highly active TPMA and Me6TREN ligands. ARGET ATRP has also been utilized in the synthesis of block copolymers (poly(n-butyl acrylate)— -polystyrene and polystyrene-Z -poly(n-butyl acrylate) [164,165] and grafting... 

We have been interested in studying molecular dynamics of polymer chains and alkyl groups anchored at one end, particularly n-alkyl glycol and glycerol derivatives, poly(n-butyl acrylate) (PBA), poly(n-butyl methacrylate) (PBMA), and poly(n-hexyl meth-... 

Poly(n-butyl acrylate). A study of the relaxation properties of PBA was initiated for several reasons. There are two backbone carbons with directly bonded protons thus the effect of the side chain on backbone motion might be determined. Also, the CH carbon should more directly reflect the distribution of correlation times necessary to begin analysis of alkyl sidechain motion. Finally, the lack of the additional chain-CH3 groups significantly loosens motional constraints in PBA. The effect of this on the overall dynamics of PBA was of interest. 

It was shown that p-hydrogen-containing nitroxides promote the controlled polymerization of not only styrenic monomers but alkyl acrylates and dienes as well. Taking this into account, a novel ttifimcdonal alkoxyamine (Scheme 28, 7) based on N-t Tt-butyl-1 -diethylphosphono-2,2-dimethylpropyl nitroxide (Scheme 28, 8) was developed for the synthesis of 3-arm PS and poly(n-butyl acrylate) (PnBuA) stars along with (PnBuA-b-PS)3 star-block copolymers. ... 

The lower n-alkyl derivatives (up to %-butyl reported) have not afforded crystalline polymers with anionic coordinated catalysts, while the branched derivatives have, such as iso-, sec-, and tert-butyl acrylate. Nevertheless, the poly(w-alkyl acrylates) prepared with a heterogeneous SrZnEt4 catalyst are stereoregular. For example, hydrolysis of amorphous poly (methyl acrylate) gives crystalline polyacrylic acid (Makimoto et al., 1961). 

Dynamic-mechanical and dielectric data for several poly-(alkyl acrylates) including poly(methyl acrylate) (PMA) (1), poly(ethyl acrylate) (PEA) (2), poly(n-butyl acrylate) (PBA) (3), and poly(cyclohexyl acrylate) (PCA) (4)... 

Fully methacrylic triblocks, containing a central rubbery poly(alkyl acrylate) block and two peripheral hard poly(alkyl methacrylate) blocks, are potential substitutes for the traditional styrene-diene-based thermoplastic elastomers (TPEs), which have relatively low service temperatures. Fully methacrylic triblock copolymers are able to cover service temperatures due to the varying Tg from — 50 C (poly(isooctyl acrylate)) to 190 C (poly (isobornyl methacrylate) [210]. Poly(methyl methacrylate)-Z)-poly(n-butyl acrylate)-Z)-poly(methyl methacrylate) triblock copolymers, which are precursors for poly(methyl methacrylate)- -poly(alkyl acrylate)-Z)-poly(methyl methacrylate) via selective transalcoholysis, have been synthesized by a three-step sequential polymerization of MMA, ferf-butyl acrylate (t-BuA), and MMA in the presence of LiCl as stabilizing ligand [211,212]. Various diblock copolymers, such as poly(methyl methacrylate)-Z)-poly( -butyl acrylate) and poly(methyl methacrylate)-Z)-poly( -nonyl acrylate), have been synthesized... 

Polymers of the lower n-alkyl acrylates have found some limited commercial use. The lowest member of the series, poly(methyl acrylate) has poor low temperature properties and is water-sensitive and its use is therefore restricted to such applications as textile sizes and leather finishes. Ethyl acrylate and butyl acrylate are the most commonly used major components of commercial acrylate rubbers. Higher acrylates are of little commercial importance. 

Poly(N-alkyl substituted acryl amides) and amongst them the most important certainly, poly(N-isopropylacrylamide) (poly(NIPAAM)), with a transition temperature of 32° C and... 

Figure 6.12 AFM images of poly(n-hutyl acrylate) (brushes made from poly(alkyl acrylate) and poly(alkyl methacrylate) backbones. The branching points are highhghted by arrows in images of dense films. Further evidence for the presence of branched macromolecules is provided by the AFM images of each brush polymers embedded in linear poly(n-hutyl acrylate) matrix (white arrows pointing to branch junctions) in panels d-f. Reproduced with permission from [23]. Copyright 2011. American Chemical Society.

Reetz and co-workers " first used metal-free carbon, nitrogen, or sulfur nudeophiles as initiators for the controlled anionic polymerization of nBA. It was thought that repladng the metal counterion in the polymerization would reduce the problem assodated with aggregation and improve the control over the polymerization. Tetrabutylammonium salts of malo-nate derivatives provided poly(n-butyl acrylate) (PnBA) of rdativdy narrow MWD at room temperature (Scheme 14). Many metal-free initiators for the polymerization of alkyl (meth) acrylates using a variety of anions and cations have been reported (Scheme 15) 208,220-224... 

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. 

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