PS-polylactide

PS-polydimethylsiloxane (PS-PDMS), polyimides containing thermally labile blocks such as poly(methyl methacrylate) (PMMA) or poly(propylene oxide) (PPO), poly(f-butylacrylate)-b-poly(2-cinnamoylethyl methacrylate) (PtBAPCEMA), poly-styrene-b-poly(methyl methacrylate) (PS-b-PMMA), PS-poly(perfluorooctylethyl methacrylate) (PS-PFMA), PS-polylactide (PS-PLA), and PS-b-poly-4-vinylpyridine (PS-PVP). 

One of the potential applications of these ABC triblock copolymers was explored by Hillmyer and coworkers in 2005 [118]. They have prepared nanoporous membranes of polystyrene with controlled pore wall functionality from the selective degradation of ordered ABC triblock copolymers. By using a combination of controlled ring-opening and free-radical polymerizations, a triblock copolymer polylactide-/j-poly(A,/V-dimethylacrylamide)-ib-polystyrene (PLA-h-PDMA-h-PS) has been prepared. Following the self-assembly in bulk, cylinders of PLA are dispersed into a matrix of PS and the central PDMA block localized at the PS-PLA interface. After a selective etching of the PLA cylinders, a nanoporous PS monolith is formed with pore walls coated with hydrophilic PDMA. 

In addition to the above-mentioned experiments using PS-based nanoparticles, the hydrophobic fluorescent dye A-(2,6-diisopropylphenyl)perylene-3,4-dicarbonacidimide (PMI) could also be successfully incorporated in phosphate-functionalized poly(methylmethacrylate) (PMMA) and PS [33], polyisoprene (PI), PS-co-PI [34], PBCA [35, 36] and polylactide (PLLA), or poly(e-caprolactone) (PCL) nanoparticles [37] in order to study the cellular response to these polymeric nanoparticles. For qualitative investigations, confocal microscopy can be used the quantitative measurements can be realized by a fluorescent activated cell sorter (FACS). 

In another example, two polymerization techniques, ATRP and ROP, were coupled to synthesize polystyrene-b-polylactide (PS-b-PLA) heterografted block brushes of high molecular weight. A diblock backbone was first prepared by the RAPT block copolymerization of solketal methacrylate and 2-(bromoisobutyryl)ethyl... 

Several PPE-containing AB and ABA block copolymers have been made and investigated for their phase behavior, optical properties, and self-assembly [60-62]. Such AB block copolymers give well-developed morphologies, fibrous self-assembled nano tubes (Figure 6.1). Surprisingly, these materials do not form the interpenetrated networks observed by Hillmyer for polylactide/polystyrene (PS) blocks [63]. 

PLA, also known as polylactide (i.e. polymerization of cyclic lactic acid, also called lactide), originally is a brittle material with lower impact strength and elongation at break, similar to another relatively brittle polymer—polystyrene (PS). However, its tensile strength and modulus are comparable to polyethylene terephthalate (PET). This is shown in Table 5. 2 as reported by Anderson et al (2008). Poor toughness limits its usage in... 

The presence of MWCNT in the polymer matrices influenced the biological properties of the nanocomposites in comparison to the pure polylactide sample (Fig.4). The proliferation of MG63 cell nanocomposites modified with MWCNT increase together with the time of culture. The highest proliferation degree after 7 days of culture for nanocomposites was observed for samples modified with l%wt. of MWCNT (MUl). For this sample the number of osteoblast-like cells after 7 days of culture was at the same level compared to the pure polylactide and control sample (Fig.4). As a negative control sample the polystyrene (PS) culture plate was used [20]. 

Figure 3.8 Comparison of GHG emissions and fossil energy requirements of representative petroleum and biobased polymers based on 1 kg of resin produced. Symbols polystyrene (PS), low-density polyethylene (LDPE), polyethylene terephthalate (PET), polypropylene (PP), polylactide (PLA), polyhydroxyalkanoates based on glucose (PHA-G), PHA based on oil (PHA-0), and PHA based on black syrup (PHA-BS).

Even though this technique has been mostly used with water-soluble polymers, such as PEO, polyvinyl ether (PVE), polyvinylpyrrolidone (PVP), and poly(acrylic acid) (PAA) [134-141], intercalation from nonaqueous solutions has also been reported [142-145]. For example, high-density polyethylene (HDPE)-based nanocomposites have been prepared by dissolving HDPE in a mixture of xylene and benzonitrile with dispersed organomodified layered silicates (OMLSs). The nanocomposite was then recovered by precipitation from tetrahydrofuran (THE) [143], Polystyrene (PS)/OMLS-exfoliated nanocomposites have also been prepared by the solution intercalation technique, by mixing pure PS and organophilic clay with adsorbed cetyl pyrid-ium chloride [146]. Similarly, several studies have focused on the preparation of polylactide (PLA)-layered silicate nanocomposites using intercalation from solution. 

In the last twenty years, many polymers have been used to make polymer nanocomposites. Thermoplastic polymers include nylon, polyaniline (PANI), " poly(s-caprolactone), polycarbonate (PC), polyether ether ketone (PEEK), polyethylene (PE), poly(ethyl acrylate) (PEA), polyisoprene (PI), polylactide (PLA), poly(methyl methacrylate) (PMMA), " polypropylene (PP), polypyrrole (PPy)," polystyrene (ps)/ i i7,27,30,49-64 poiy inyl acetate) (PVAc), poly(vinyl alcohol) (PVA), poly(vinyl chloride) (PVC) and thermoplastic polyurethane (TPU), and thermosets include Bakelite, butadiene rubber, epoxy,polydimethylsiloxane (PDMS), polyurethane (PU), styrene-butadiene rubber (SBR) and unsaturated polyester resin. 

The solubility of various gases in polyma melts has been investigated by sevaal researchers. Sato et al. [18-22] studied the dissolution of CO2 and N2 in PS, polypropyloie (PP), high-daisity polyethylene (HDPE), and poly(vinyl acaate) (PVAc) bOween 313 and 473 K and at pressures up to 20 MPa Areaat et al. [23] investigated the solubility of supacritical carbon dioxide (SC-CO2) in LDPE, HDPE, and PP. Li et al. [24, 25] studied the solubility of CO2 in PP and polylactide (PLA). 

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