• Environmental Engineering Research
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• 제11권4호
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• pp.208-216
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• 2006

In order to create a single flocculant/dual flocculation system, polyacrylamide-co-trimethyl ammonium ethyl acrylate chloride (TAEAC) polymers with varying molecular weights and structures were prepared for use of flocculants. The higher the cationic density of the polymer is higher, the higher was the conversion rate and the ratio of monomer. An acrylamide as nonionic monomer was less reactive than a TAEAC as cationic monomer. The branched polymer which was polymerized with a cross-linking agent, N, N-methylene bis-acrylamide had a higher stability and higher viscosity than a linear polymer but its dewatering efficiency was poor in a single flocculation system. In the case of single flocculant/dual flocculation, the branched polymer has better flocculation efficiency and the water content of the dewatered cakes was lower than the others, as the result of a re-flocculation effect. The optimum conditions for dual flocculation are a sequence in which the $1^{st}$ and $2^{nd}$ dosage are 75% and 25%/total dosage of a single flocculation system. The dewatering efficiency of a dual flocculation system is improved considerably from 10 to 25% under the experimental conditions used herein.

• Macromolecular Research
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• 제14권3호
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• pp.287-299
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• 2006

To successively synthesize star-branched polymers, we developed a new iterative methodology which involves only two sets of the reactions in each iterative process: (a) an addition reaction of DPE or DPE-functionalized polymer to a living anionic polymer, and (b) an in-situ reaction of 1-(4-(4-bromobutyl)phenyl)-1-phenylethylene with the generated 1,1-diphenylalkyl anion to introduce one DPE functionality. With this methodology, 3-, 4-, and 5-arm, regular star-branched polystyrenes, as well as 3-arm ABC, 4-arm ABCD, and a new 5-arm ABCDE, asymmetric star-branched polymers, were successively synthesized. The A, B, C, D, and E arm segments were poly(4-trimethylsilylstyrene), poly(4-methoxystyrene), poly(4-methylstyrene), polystyrene, and poly(4-tert-butyldimethylsilyloxystyrene), respectively. All of the resulting star-branched polymers were well-defined in architecture and precisely controlled in chain length, as confirmed by SEC, $^1H$ NMR, VPO, and SLS analyses. Furthermore, we extended the iterative methodology by the use of a new functionalized DPE derivative, 1-(3-chloromethylphenyl)-1-((3-(1-phonyletheny1)phenyl) ethylene, capable of introducing two DPE functionalities via one DPE anion reaction site in the reaction (b). The number of arm segments of the star-branched polymer synthesized by the methodology could be dramatically increased to 2, 6, and up to 14 by repeating the iterative process.

• 한국응용과학기술학회지
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• 제17권2호
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• pp.76-82
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• 2000

The relative reactivities of branched and linear polycarbonates were investigated by measuring unreacted chloroformate concentration. It was found that the polymerization for the branched polymer proceeded ca. 10 times faster than that for the linear polymers. The effect of catalyst on a condensation step was studied by changing the amount of TEA (triethylamine) at $t_{0}$ and $t_{60}$ with keeping constant amount of TEA. The viscosity average molecular weight for the obtained branched polycarbonates were measured and compared with those of linear polycarbonates. It was found that the viscosity molecular weights of the obtained polymers decreased nonlinearly as wt % of added oligomer increased. The solution viscosities in methylenechloride for linear and branched polycarbonate increased nonlinearly as the content of polymer increased.

• 한국염색가공학회지
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• 제4권4호
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• pp.81-89
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• 1992

Graft polymers of alginic acid-PMMA, different in composition and Mv of branched PMMA, were prepared by emulsion graft polymerization at various MMA concentrations. In aqueous dispersion solution, the adsorption of graft polymer on the montmorillonite was carried out to modify the surface property of powder, and the adsorption of PMMA in organic solvents (acetone, benzene) on the modified surface of powder were observed. The results obtained were as follows. 1. In emulsion graft polymerization of MMA on the sodium alginate in aqueous solution, SA conversion, MMA conversion and % grafting were increased with increasing MMA concentration where as graft efficiency was decreased. 2. The adsorption amount of graft polymer was increased with the elevation of temperature and the increased of dispersion concentration and with the increase of branched PMMA composition of graft polymer. 3. In organic solvent, the adsorption of PMMA on the surface modified particle was proceeded by the orientation along the stretched branched PMMA of adsorbed graft polymer which is in radial direction to the particle surface. 4. The adsorbed amount of PMMA was increased as the temperature and concentration of PMMA solution, the branching of adsorbed graft polymer and the solvency of solvent were increased.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.2
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• pp.251-256
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• 2006

The purpose of this study was to confirm multiple retention system of C-PAM, A-PAM and Inorganic micro particles vs. traditional micro particle system and dual polymer system by measuring retention, drainage and formation using RDA HSF and Techpap 2D -F Sensor The benefits of dual polymer system were easy to use, low chemical consumption and good retention property but defect was worse drainage property than inorganic microparticle systems. On the other hand, Inorganic microparticle system had benefit of good drainage effect but defects were difficult to use, high chemical consumption. Therefore, we tried to find optimal morphology of polyacrylamide and applied to multiple retention system of C-PAM, A-PAM and inorganic microparticles to compensate defects of both of retention systems. As a result, we found the performance of branched C-PAM, branched A-PAM and inorganic micro particle triple system was more appropriate than traditional inorganic mircoparticle systems or dual polymer systems by comparing retention, drainage and formation.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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• pp.203-203
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• 1999

Mass spectrometry technique provides the molecular weight distribution, data on the sequence of repeat units, polymer additives, and impurities, and structural information. time-of-Flight secondary Ion Mass Spectrometry (TOF-SIMS) has been used for structural characterization of various polymers1-2. the masses of repeat units and terminal groups and molecular weight distributions of polymers have been determined from their TOF-SIMS spectra. TOF-SMIS provides good sensitivity and structural specificity for high mass ions so that intact oligomers and large polymer fragments are observed. In this study, we investigated the detailed structural information on the oligomers and fragment ions of branched poly(1,3-butylene adipate) and branched poly[di(ethylene glycol) adipate] and the transesterification products of branched polyesters with trifluoroacetic acid or chloro difluoroacetic acid. Branched polyesters were chosen because they are important polymers but difficult to characterize; thus branched polyesters provide challanging test for TOF-SIMS. TOF-SIMS spectra of polyesters are obtained from thin polymer films cast from solution on a silver substrate. A good solvent for a polumer solution disrupts intermolecular forces between polymer chains but leaves the polumer intact. Transesterification reactions are potentially useful for characterization of high molecular weight and intractable polyesters. Transesterification products of polyesters and trifluoroacetic acid or an integral number of polyester repeat units and an additional diol. The progress of such reactions was monitored using peak intensities of reactants and products in TOF-SIMS spectra. The increasing abundance of tagged ions indicates that the reaction has progressed with time.

• 폴리머
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• 제36권2호
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• pp.245-250
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• 2012

장쇄분지(long chain branch, LCB)를 가지는 분지화된 폴리프로필렌(polypropylene, PP)이 세 종류의 분지제(branching agent)를 이용하여 고상(solid state)에서 제조하였다. 분지화된 PP의 화학구조, 비등온결정화 거동 및 복합점도를 적외선분광기(FTIR), 시차주사열용량분석기(DSC), 광학현미경 그리고 동적유변측정기(ARES)를 이용하여 관찰하였다. 분지화된 PP의 화학구조는 3100 $cm^{-1}$에서 나타나는 분지제의 =C-H 신축진동을 이용하여 확인하였다. PP-D-0-3과 PP-F-0-3의 경우 순수 PP와 비교하여 용융온도에 큰 변화를 보이지 않은 반면 HQ를 사용한 경우에는 용융온도의 감소를 나타내었다. 이는 분지화 반응보다 분해반응이 우세하여 나타나는 현상으로 해석되고, 복합점도의 감소를 통해 확인하였다. 분지화된 PP의 비등온결정화 거동은 Avrami 방정식을 이용하여 분석하였다. PP의 Avrami 지수는 3의 값을 나타내었고, DVB와 FS로 처리된 분지화 PP의 경우는 3보다 약간 작은 값을 나타내었다. Kissinger 방법에 의해서 계산된 분지화 PP의 활성화에너지는 순수 PP의 25 kJ/mol과 큰 차이를 보이지 않았다.

• Macromolecular Research
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• 제16권8호
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• pp.686-694
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• 2008

We studied the molecular shapes and structural characteristics of a 33-armed, star polystyrene (PS-33A) and two $3^{rd}$-generation, dendrimer-like, star-branched poly(methyl methacrylate)s with different architectures (pMMA-G3a and PMMA-3Gb) and 32 end-branches under good solvent and theta ($\Theta$) solvent conditions by using synchrotron small angle X-ray scattering (SAXS). The SAXS analyses were used to determine the structural details of the star PS and dendrimer-like, star-branched PMMA polymers. PS-33A had a fuzzy-spherical shape, whereas PMMA-G3a and PMMA-G3b had fuzzy-ellipsoidal shapes of similar size, despite their different chemical architectures. The star PS polymer's arms were more extended than those of linear polystyrene. Furthermore, the branches of the dendrimer-like, star-branched polymers were more extended than those of the star PS polymer, despite having almost the same number of branches as PS-33A. The differences between the internal chain structures of these materials was attributed to their different chemical architectures.

• 폴리머
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• 제36권4호
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• pp.440-447
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• 2012

분지화된 폴리에스테르계 공중합체를 제조하고, 공중합체의 분자량, 용융점도, $T_g$, 1/2 method temperature($T_{1/2}$) 및 레올로지 특성을 고찰하여 레이저 프린터 토너 바인더로의 적용을 검토하였다. 디메틸테레프탈레이트(DMT), 에틸렌글리콜(EG), 2,2-bis(4-(2-hydroxypropoxy)phenyl)propane(HPP)으로 제조한 선형공중합체는 분자량이 낮고, 용융탄성이 낮아 이를 개선하기 위하여 분지제로 3 또는 4 관능기를 가진 2-(hydroxymethyl)-2-ethylpropane-1,3-diol(trimethylol propane, TMP), 2,2-bi(hydroxymethyl)-1,3-propanediol(pentaerythritol, PER), 1,2,4-benzenetricarboxylic anhydride(trimellitic anhydride, TMA), 글리세롤 등을 첨가하여 분지화된 공중합체를 제조하였다. 분지제의 함량과 종류에 따른 열적, 레올로지 특성을 고찰하였다. 분지제의 함량이 15 mol% 이상 첨가한 공중합체는 $140^{\circ}C$ 정도의$T_{1/2}$ 값을 가지고, 높은 분자량과 용융탄성을 나타내어 토너를 융착 인쇄하는 레이저 프린터의 핫멜트 토너로서 적당하였다.

• 폴리머
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• 제35권4호
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• pp.356-362
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• 2011

폴리카보네이트(polycarbonate, PC)에 화학적 구조가 다른 두 가지의 분지제를 첨가하여 용융중합으로 분지형 폴리카보네이트(branched PC, B-PC)를 합성하였다. 분지제의 함량은 0.001~0.005 mol% 내에서 조절하였다. 합성된 PC의 화학구조는 FTIR, $^1H$ NMR파 $^{13}C$ NMR 스펙트럼을 이용하여 확인하였으며, 분자량, 유리전이온도 및 분해온도는 GPC, DSC와 TGA를 이용하여 측정하였다. Phloro type의 분지제를 가지는 B-PC의 분자량에 낮은 값을 보여주었으며, 유리전이온도는 분자량에 따라 증가하였다. 두 형태의 B-PC 모두 선형 PC와 비교하였을 때 낮은 주파수(frequency) 영역에서 복합점도(complex viscosity)가 높게 나타났고, shear thinning 현상이 크게 나타났다. Shear thinning의 정도를 표시하는 power law index(n)는 선형회귀분석에 의해 계산되었고 0.483~0.996 범위의 값을 보여주었다. Phloro 타입의 B-PC가 높은 shear thinning 경향을 보였으며 이들 B-PC의 유변학적 특성은 동적유변측정기를 이용하여 측정하였다.