PMMA-block-poly

Table 1. Preparation of i -PMMA-block poly(EMA) with t-C4H9MgBr in toluene at -60°C ...

Determined from NMR spectra by peak elimination method S Triblock copolymer PMMA-block-poly(EMA)-block-PMMA. 

Although the potassium superoxide route can be universally applied to various alkyl methacrylates, it is experimentally more difficult than simple acid hydrolysis. In addition, limited yields do not permit well-defined hydrophobic-hydrophilic blocks. On the other hand, acid catalyzed hydrolysis is limited to only a few esters such as TBMA, but yields of carboxylate are quantitative. Hydrolysis attempts of poly(methyl methacrylate) (PMMA) and poly(isopropyl methacrylate) (PIPMA) do not yield an observable amount of conversion to the carboxylic acid under the established conditions for poly(t-butyl methacrylate) (PTBMA). This allows for selective hydrolysis of all-acrylic block copolymers. 

Narrow molecular weight distribution PMMA-fc-poly(2-perfluorooclyle-thyl methacrylate) block copolymers (Scheme 2) were synthesized in THF at... 

Figure 8.12 TEM photographs of triblock copolymers dispersed in a DGEBA-diamine epoxy network. The triblock copolymer is polystyrene-b-polybuta-diene-b-poly(methyl methacrylate), and the epoxy hardener is (a) -methylene bis [3-chloro-2,6 diethylaniline], MCDEA, and (b) 4,4 -diamino diphenyl sulfone, DDS. In the case of the epoxy system based on MCDEA, the PMMA block is miscible up to the end of the epoxy reaction. In the case of the epoxy system based on DDS, the PMMA block phase-separates during reaction. (From LMM Library.)... 

Block copolymers can be produced from terminally borane-containing polyolefins. These borane-containing POs can be synthesized by the metallocene-catalyzed (co)polymerization of olefin(s) monomer with 9-BBN as a chain transfer agent or by the metallocene catalyzed copolymerization of olefins with allyl-9-BBN [55,56], as referred to above. Alternatively, borane-containing POs were prepared by hydroboration of terminally unsaturated PO, for instance, terminally vinyl PE and terminally vinylidene PP [33-35,57]. Such method could produce diblock copolymers, such as polyethylene-block-poly(methyl methacrylate) (PE-fo-PMMA), polypropylene-foZock-poly(methyl methacrylate) (PP-fc-PMMA), polypropylene-foZock-poly(butyl methacrylate) (PP-fc-PBMA), and PP-fc-PS. 

The dual function of the precatalysts 4 opened the way to well-controlled block polymerization of ethylene and MMA (eq. (5)) [89, 90]. Homopolymerization of ethylene (Mn = 10000) and subsequent copolymerization with MAA (Mn 20000) yielded the desired linear AB block copolymers. Mono and bis(alkyl/silyl)-substituted flyover metallocene hydride complexes of type 8 gave the first well-controlled block copoymerization of higher a-olefins with polar monomers such as MMA or CL [91]. In contast to the rapid formation of polyethylene [92], the polymerization of 1-pentene and 1-hexene proceeded rather slowly. For example, AB block copolymers featuring poly( 1-pentene) blocks (M 14000, PDI = 1.41) and polar PMMA blocks (M 34000, PDI = 1.77) were obtained. Due to the bis-initiating action of samarocene(II) complexes (Scheme 4), type 13-15 precatalysts are capable of producing ABA block copolymers of type poly(MMA-co-ethylene-co-MMA), poly(CL-co-ethylene-co-CL), and poly(DTC-co-ethylene-co-DTC DTC = 2,2-dimethyltrimethylene carbonate) [90]. 

First experiments which focused on the variation of the conformational properties have been performed by Brown et al. [240], who studied the role of the interactions between matrix and brush polymers (enthalpy driven brush swelling, see Eq. 59). They used a series of polystyrene (PS)-poly(methyl methacrylate) (PMMA) symmetric diblock copolymers with different blocks labeled by deuterium, placed at the interface between PMMA and poly(2,6-dimethylphenylene oxide) (PPO) homopolymers. A double brush layer was created with PMMA blocks dangling into (neutral) PMMA homopolymer and PS blocks immersed in favorably interacting PPO melt (x=Xps/ppo<0)- The SIMS profiles obtained showed that the PS side of the block copolymer is stretched by at least a factor of 2 with respect to the PMMA side. 

Fig. 1 a-d Chemical structures of linear peptide block copolymers a 1,2-Polybutadiene-block-poly(L-glutamate) (PB-h-PLGlu). b Polybutadiene-Wock-poly(L-lysine) (PB-h-PLLys). c Poly (L-glutamate)-Wock-poly(L-lysine) (PLGlu-h-PLLys). d Poly(methyl methacrylate)-Wock-peptide-Wock-poly(methyl methacrylate) (PMMA-h-peptide-h-PMMA)... 

Before obtaining the experimental results for the proposed covalidation effort, two prior steps were required, namely, the design and fabrication of the microchannels, and the assembly of an experimental platform that would allow for the easy exchange of different microchannel setups. A PMMA poly-methyl methacrylate prism of low thermal conductivity was employed as the structural support of the metallic plates that form the microchannels, chosen to be made of electronic grade copper (upper plate) and brass (lower plate). Micro-machining of the PMMA block and of the metallic plates was accomplished and the setup was assembled according to Fig. 2 below. 

Ring-opening metathesis polymerization (ROMP) of 1,4-cycloocladiene was used to prepare poly(l,4-B) terminated with halo end groups.This was then used as a macroinitiator of ATRP with heterogeneous Cu bpy catalysts to fonn PS-block- >o y 1,4-B)-b/oc A-PS and PMMA-Woc/ -poly( 1,4-B)-6/ot A-PMMA,... 

Thomas reported a very similar study (decomposition of Co2(CO)8 in a hydrocarbon in the presence of a terpolymer), which resulted in the formation of nanoparticies of 2-30 nm according to the reaction conditions. The author was particularly interested in the modification of the magnetic properties due to dipolar couplings as a function of the separation of the particles.Similar procedures are still used for the production of cobalt particles in organic matrices. For example, a recent paper reports thermolysis reactions of Co2(CO)8 in a block co-polymer, PS2S3oo- -MMA2S9oo, hence producing cobalt nanoparticies embedded in the poly(methylmethacrylate) (PMMA) blocks. ... 

Methyl methacrylate (MMA) and sodium styrene sulfonate (SSNa) are water-soluble. These polymers behave like a low MW surfactant as they form micelles in aqueous solution in which the hydrophobic part is directed towards the centre and the hydrophilic part is situated on the periphery of the micelle. Owing to such features, amphiphilic block copolymers have wide-ranging applications in drugs, pharmaceuticals, coatings, cosmetics and paints. They also exhibit very high antibacterial activities. Oikonomou and co-workers used ATRP to prepare amphiphilic block copolymers, consisting of polymethyl methacrylate (PMMA) and poly (sodium styrene sulfonate) (PSSNa) blocks [18]. The synthesis methods are described below. 

In our opinion, the results obtained for proteins [65, 66] do not appear contradictory. Undoubtedly, the fractal dimension presented in the study [65] is the spectral dimension dj. Its value (d = 1.65) does not seem too great either, if one takes into account that the values dj = 1.65-1.80 were obtained for block poly(methyl methacrylate) (PMMA) [36]. These large values of spectral dimension can be due to several reasons, first of all, to the high connectivity of the polymer chain [28]. 

Examples of such compatibilized systems that have been studied include EPDM/PMMA blends compatibilized with EPDM- -MMA, polypropylene/polyethylene blends with EPM or EPDM, polystyrene/nylon-6 blends with polystyrene/nylon-6 block copolymer, and poly(styrene-co-acrylonitrile)/poly(styrene-co-butadiene) blends with butadiene rubber/PMMA block copolymer. 

Block copolymers consisting of PPV and poly(methyl methacrylate) (PMMA) blocks, can be obtained by atom transfer radical polymerization. The thermal stability is slightly improved in comparison to neat PPV derivates by the introduction of PMMA blocks. The onset of thermal degradation starts around 200°C. 

Table 1.1 Reported techniques to selectively degrade one copolymer block. Poly(styrene) PS, poly (dimethylsiloxane) PDMS, poly(ethyleneoxide) PEO, poly(isoprene) PI. poly(lactic acid) PLA. poly(methyl methacrylate) PMMA, poly(vinylpyridine) PVP, 3-pentadecylphenol PDP...

Stenert, M., Doring, A., and Bandermann, F. 2004. Poly(methyl methacrylate)-block-polystyrene and polystyrene-block-poly( -butyl acrylate) as compatibihzers in PMMA/PNBA blends, e-Poly-mers 15,1-16. 

After these initial considerations, the complete analysis of a number of diblock copolymers of styrene and methyl methacrylate shall be discussed in detail. The poly(styrene-ftlodc-methyl methacrylate)s under investigation were prepared via anionic polymerization of styrene and subsequent polymerization of methyl methacrylate, varying molar mass and composition (B1-B3). The polystyrene precursors (P1-P3) were isolated and characterized separately. As the PMMA block is the more polar block in the block copolymer, a polar (silica gel) column was chosen for establishing the critical point of PMMA. According to case (1) in Fig. 14, the PS block is then eluted in the SEC mode. The behavior of PMMA of different molar masses on silica gel Si-100 in eluents comprising methylethylketone and cyclohexane is shown in Fig. 15A [37]. 

Stoykovich et al. ° formed nonregular patterns by combining ternary blends of PS-block-poly(methyl methacrylate) (PS-b-PMMA) diblock copolymers and PMMA homopolymers on chemically nanopattemed substrates. The ternary... 

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