Sedimentation polymerization of aqueous solutions of N-isopropylacrylamide (NIPA) was carried out to prepare porous poly(N-isopropylacrylamide) (PNIPA) beads. When small amounts of DMF and a radical accelerator were added to the monomer solution, the polymerization proceeded smoothly to give polymer beads with a very narrow size distribution. The rate of swelling of the resulting bead increased with increasing crosslinker content and was also affected by the type of crosslinker used. When amounts higher than 1 mol % N,N 0 -methylenebisacrylamide or 3 mol % diethylene glycol diacrylate (DEGDA) were used as a crosslinker, the resulting beads underwent rapid swelling in water at 208C, reaching the equilibrium within 5 min. A cross-sectional photograph of a typical dried bead showed that it had a very complex morphology consisting of a large and irregular void, highly porous region, and nonporous region. The swelling rate was directly dependent on the morphology of the beads. PNIPA beads with well-developed porous areas show a high swelling rate. Although PNIPA beads produced from DEGDA had welldeveloped porous structures, they were able to effectively concentrate blue dextran from the dilute aqueous solution.

ABSTRACT:Polymers containing allylic and benzylic carbonate repeating units have been prepared by phase-transfer catalyzed polycondensation of activated his-carbonates or carbamates and diols. The polymers are highly susceptible to thermal depolymerization and revert to small molecules when heated to temperatures which vary from 140 to 230oC depending on structure. The thermolysis temperatures are reduced to well below I 00°C if catalytic amounts of acid are added to the polycarbonates. The thermolysis or acidolysis of bis allylic or benzylic carbonates provides a convenient route to aromatic compounds as demonstrated with both models and polymers. The polycarbonates can be used to formulate highly sensitive resist materials with potential for selfdevelopment of positive images. Some benzylic polycarbonates which produce polymerizable divinyl monomers upon thermolysis can be used to create negative images in a process which includes both depolymerization and photocrosslinking.KEY WORDS Radiation-Sensitive I Polycarbonate I Resist I Chemical Amplification I Thermolysis I Phase-Transfer Catalysis I Thermoreversible I Polycondensation I Acidolysis I Over the past decade, the development of resist materials with improved properties has proceeded at a noticeably faster pace as various laboratories strive to implement a variety of new conceptual designs. 1 Of particular interest in the context of this report are efforts to develop polymers which possess high sensitivities and can be imaged in high quantum yield process<;s. Early examples of such systems include glycidyl methacrylate copolymers and similar materials containing pendant epoxide groups 2 which can be crosslinked in chain-wise fashion by exposure to radiation. However, a serious drawback to the use of these resists, and indeed of most materials which operate on the basis of ring-opening or vinyl polymerizations of pendant groups, is the existence of "dark reactions". 1 These are processes in which crosslinking continues even after irradiation has been completed, a phenomenon which can seriously impair resolution in some applications.• Taken in part from

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Arsenic contamination of groundwater is a serious concern worldwide. The research gaps in removing arsenic are selectivity, regeneration and effective removal rate at neutral pH levels. In this study, we discussed the reasons of the high arsenic adsorption from groundwater of our previously developed adsorbent, a cationic polymer gel, N,N -dimethylamino propylacrylamide, methyl chloride quaternary (DMAPAAQ), loaded with iron hydroxide. We used a transmission electron microscope (TEM) and thermogravimetric analyser (TGA) to detect the iron contents in the gel and ensure its maximum impregnation. We found that the gel contains 62.05% FeOOH components. In addition, we used the Mössbauer spectroscopy to examine the type of impregnated iron in the gel composite and found that it was γ-FeOOH. Finally, we used Fourier transform infrared spectroscopy (FTIR) to examine the surface functional groups present in the gel and the differences in those groups before and after iron impregnation. Similarly, we also investigated the differences of the surface functional groups in the gel, before and after the adsorption of both forms of arsenic. To summarize, this study described the characteristics of the gel composite, which is selective in adsorption and cost effective, however further applications should be investigated.

Poly[4‐(4‐nitrobenzyloxy)styrene] was synthesized with a high degree of etherification by the reaction of poly(4‐hydroxystyrene) (PHST) with p‐bromomethylnitrobenzene (p‐BMNB) using 1,8‐diazabicyclo‐[5,4,0]‐7‐undecene (DBU) in hexamethylphosphoramide (HMPA). Poly[4‐(3‐nitrobenzyloxy)styrene] and poly[4‐(2‐nitrobenzyloxy)styrene] were also prepared with a high degree of etherification by the corresponding reaction with m‐ or o‐BMNBs. However, the degrees of etherification of PHST with these BMNBs were relatively low when the reactions were carried out in other aprotic polar solvents such as DMF, DMSO, and N‐methyl‐2‐pyrrolidone. On the other hand, poly(4‐introbenzyl methacrylate) (PPNBMA), poly(3‐nitrobenzyl methacrylate) (PMNBMA), and poly(2‐nitrobenzyl methacrylate) (PONBMA) were synthesized with a high degree of esterification by the reaction of poly(methacrylic acid) with the corresponding BMNBs using DBU in DMSO at 30°C. The photochemical properties of the resulting poly(nitrobenzyl methacrylate)s were examined, and it was found that the rates of photodecomposition of PPNBMA and PMNBMA were promoted by the addition of tributylamine and trifluoromethanesulfonic acid, respectively. However, the rate of photodecomposition of PONBMA was not affected by addition of the base or the acid.