• Macromolecular Research
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• 제15권6호
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• pp.560-564
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• 2007

The photostabilization and cure kinetics of UV-curable, optical resins containing various formulations of photostabilizers were investigated to determine the system with the highest cure conversion and durability. Photo-DSC analysis revealed that increasing the concentration of a UV absorber (UVA) decreased both the crosslink density and the cure rate due to competition for the incident photons between the photoinitiator and the UVA, whereas including a hindered amine light stabilizer (HALS) hardly affected either the cure conversion or the cure rate due to its very low absorption of 365 nm. This result was confirmed by FTIR-ATR spectroscopy and UV-visible spectroscopy analyses. QUV ageing experiments showed that the cure conversion and durability were the highest for the UVA/HALS formulation at a ratio of 1 : 2, which is due to their synergistic action.

• Macromolecular Research
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• 제10권3호
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• pp.168-173
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• 2002

Unstabilized low-density polyethylene (LDPE) films and films formulated with hindered amine light stabilizer (HALS) were exposed to UV-radiation; and the physicochemical changes during photooxidation processes have been investigated using tensile, FTIR spectre-photometric and thermal analytical (DSC) techniques. The dependence of tensile properties (elongation- and stress-at-break), carboxyl index and heat of fusion on UV-irradiation time have been discussed. The use of HALS is found to be effective in maintaining the UV-mechanical properties of the LDPE films. The experimental results showed that there exists no correlation between mechanical properties and carbonyl index, whereas crystallinity correlates well with carbonyl index in unstabilized and stabilized films for irradiation times greater than 100 h. The rate of formation of carbonyl groups is found to be dependent on UV exposure time. Crystallinity of the film samples is strongly influenced by both exposure time and presence of HALS.

• Bulletin of the Korean Chemical Society
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• 제10권1호
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• pp.12-15
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• 1989

Various tertiary amides have been subjected to the reduction by borane-THF in the presence of trimethyl borate at $0^{\circ}C$ and the product ratio of alcohol and amine have been analyzed in order to find out the possible way to obtain one product exclusively on the basis of the structure of amides. In the case of N,N-dimethyl derivatives of both linear aliphatic and aromatic amides the corresponding alcohols were produced predominantly. However, the bulkier tertiary amides such as N,N-diethyl and hindered acid derivatives afforded amines rather than alcohols. The mechanism of borane reduction of tertiary amides is also discussed.

• Bulletin of the Korean Chemical Society
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• 제21권1호
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• pp.61-64
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• 2000

FT-IR/ATR analysis shows that the oriental lacquer coating network degrades mostly in the unsaturated side chain. The rate of increase in carbonyl intensity (a measure of photodegradation) during the accelerated weathering test was substantially different for the unstabilized and stabilized samples; adding 2 wt% HALS into the oriental lacquer formulation enhanced photostabilization up to three times. Weight loss measurements, another indication of photodegradation, and SEM analysis support this conclusion. Despite the presence of the photo-stabilizer, the other properties of the lacquer were not significantly affected. In particular, the curing behavior of purified lacquer (PL) and HALS-stabilized samples is similar, although the in-situ DETA analysis showed that addition of HALS can slightly retard the cure reaction rate in oriental lacquer coating. It is hypothesized that this cure retardation may be related to the salt formation between HALS and acid of oriental lacquer.

• Journal of the Korean Wood Science and Technology
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• 제46권5호
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• pp.449-470
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• 2018

본 총설에서는 외부에 사용되는 목재를 풍화인자로부터 보호하기 위해 실행되고 있는 최근의 연구동향에 대해 조사 분석하였다. 주요 기상열화 인자로부터 목재의 표면 보호를 위한 연구 동향에 대하여 조사한 결과 다음과 같은 결론을 얻었다. 목재보존제로 사용된 크롬, 구리 등의 무기화합물이 목재를 기상열화로부터 보호할 수 있는 것으로 보고되었다. 또한 ACQ처리 목재의 표면에 wax나 oil같은 소수성물질과 UV 흡수제, HALS(Hindered Amine Light Stabilizers) 등을 방부목재 표면에 precoating하면 기상열화 저항성을 강화할 수 있다고 보고되었다. 또한 방부목재 표면에 불투명 도막형성의 페인트/스테인 및 반투명스테인등이 기상열화방지에 대한 시너지 효과가 높힐수 있다는 보고들이 다수 있었다. 또한 방부목재의 표면보호를 위한 재도장 처리의 필요성이 시사되었다. 투명성의 도막에 UV방지를 위한 첨가물로서 미세입자의 ZnO 또는 $TiO_2$, Co, Cr, Fe, Mn, Ni과 Ti 등의 금속이온, Tris-resorcinol triazine derivatives, triazine 및 Benzotriazole과 같은 UV흡수제 등이 소개되었다. Methylation, acetylation 또는 alkylation 등과 같이 화학적으로 개질된 경우에는 이로 인한 중량증가가 높은 경우 기상열화 방지효과가 상승된다는 연구들이 소개되었다, 열처리목재의 기상열화 저항성에 대해서는 여러 가지 상반되는 연구보고 들이 있었고, UV저항성을 지닌 도장의 필요성이 강조된 보고가 있어 보다 심도 있는 연구의 필요성이 시사되었다.

• Korean Chemical Engineering Research
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• 제47권2호
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• pp.185-189
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• 2009

10 wt% 암모니아수 흡수제에서 이산화탄소 흡수속도를 교반셀 반응기를 이용하여 293~337 K 범위에서 측정하였다. 암모니아 흡수제와 이산화탄소의 반응속도를 아레니우스 식으로 나타내었으며 활성화에너지는 50.42 kJ/mol였다. 2-Amino-2-methyl-1-propanol(AMP), 2-amino-2-methyl-1,3-propandiol(AMPD), 2-amino-2-ethyl-1,3-propandiol(AEPD)의 입체장애아민 첨가제가 1 wt% 함유된 흡수제에서의 이산화탄소 흡수속도를 측정하였다. 아민 첨가제들은 흡수속도에 영향을 주었으며 1 wt%의 AMP를 첨가한 경우 반응속도 상수는 약 53% 증가하였다.

• 한국대기환경학회지
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• 제21권5호
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• pp.507-513
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• 2005

Increasing amounts of anthropogenic $CO_2$ emitted to the atmosphere are believed to be a significant factor in global climate change. Hence, the method of chemical absorption has been suggested to separate and recover acid gases such as $CO_2$. In this study, the characteristics of absorption and regeneration of $CO_2$ for the absorbent which adding HMDA (hexamethylenediamine) into AMP (2-amino-2-methyl-1-propanol), hindered amine, was investigated in lab-scale absorption/regeneration reactor. As a result of this study, the removal efficiency of $CO_2$ increased when adding $5.9\%,\;11.7\%\;and\;23.4\%$ HMDA into $30\%$ AMP respectively. Also, the removal efficiency of $CO_2$ increased $6.5\%,\;8.4\%,\;10.3\%$ respectively as compared to AMP alone when the gas flow rate was 7.5 SL/min. In addition, all absorbents used in the study revealed the high stripping efficiency, which was almost $99\%$, at the temperature of $110^{\circ}C$. Thus, the regeneration tower should be operated at $110^{\circ}C$. At this time, the concentration of exhausted $CO_2$ was higher than $99\%$.

• Mass Spectrometry Letters
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• 제3권1호
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• pp.25-28
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• 2012

Paint Spray is developed as a direct sampling ionisation method for mass spectrometric analysis of additives in polymer-based surface coatings. The technique simply involves applying an external high voltage (5 kV) to the wetted sample placed in front of the mass spectrometer inlet and represents a much simpler ionisation technique compared to those currently available. The capabilities of Paint Spray are demonstrated herein with the detection of four commercially available hindered amine light stabilisers; TINUVIN${(R)}$770, TINUVIN${(R)}$292, TINUVIN${(R)}$123 and TINUVIN${(R)}$152 directly from thermoset polyester-based coil coatings. Paint Spray requires no sample preparation or pre-treatment and combined with its simplicity requiring no specialised equipment makes it ideal for use by non-specialists. The application of Paint Spray for industrial use has significant potential as sample collection from a coil coating production line and Paint Spray ionisation could enable fast quality control screening at high sensitivity.

• 한국응용과학기술학회지
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• 제26권2호
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• pp.171-178
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• 2009

A comparative analysis of the hindered amine light stabilizers (HALS) and UV abosrber (UVA) and their respective photostabilizing effect on wood plastic composites (WPCs) are reported in this study. The influence of accelerated weathering on the mechanical properties of the composites and the microscopic morphology of a degraded layer on the cross section and the surface were studied. UV absorbers were more efficient at preventing composite lightening than was UV stabilizer. The amount of whitening decreased with the increase of photostabilizers. With the addition of a UV absorber (Tinuvin360), the tensile modulus and strength of the composites increased slightly. However, the addition of a light stabilizer (Tinuvin770) and a UV absorber decreased the tensile modulus and strength of the composites. After 250 and 500 hr exposure, tensile modulus and strength of the un stabilized and stabilized composites decreased. The tensile strength of UV absorber (Chimassorb81)-stabilized composites was significantly greater than that of control and light stabilizer (Tinuvin770)- and UV absorber (Tinuvin360)-stabilized composites. UV absorber-stabilized samples showed less whitening and photodegradation than control and light stabilizer-stabilized samples.

• Journal of Photoscience
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• 제3권3호
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• pp.167-169
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• 1996

Absorption of UV light induces photocleavage of polymer chains to produce free radicals which initiate photodegradation of the polymer molecules. Discoloration, cracking of surface, stiffening, and decreasing of mechanical properties of polymeric products occur as a result of photodegradation of the polymers. Photostabilizers are added to the polymer systems in order to minimize the unwanted effects of UV light. It is well known that Hindered Amine Light Stabilizers (HALS) are one of the most effective photostabilizer for polymers.' HALS have been used in a large number of commercial polymers and predominantly used in styrenic and engineering plastics. They are efficient and cost-effective in many applications despite their high prices. However, low molecular weight HALS vaporize easily, emitting harmful amines, and have poor extraction resistance, decreasing their photostabilization effect. They also decompose during processing and migrate within the polymers resulting in deposition on the polymer surfaces called 'blooming". These drawbacks of low molecular HALS can be overcome by use of the polymeric HALS. We have been studying photochemical reactions of the polymer systems. The present paper reports the preparation of a new polymeric photostabilizer containing HALS groups and their stabilization effects on photooxidation of polystyrene. The synthetic scheme for the preparation of polymeric photostabilizers containing HALS groups were shown at Scheme 1. N-[(Chloroformyl) phenyl]maleimide (CPMI) and N-[4-(chlorocarbonyl) phenyl]maleimide (CPMIC) were prepared by the known procedure. N[4-N'-(2,2,6,6-tetramethyl-4-piperidinyl)aminocarbonyl-phenyl] maleimide (TMPI) was prepared by the reaction of CPMI with 4-amino-2,2,6,6-tetramethylpiperidine (ATMP).