Earticle

본 연구에서는 PP/EVOH 다층 구조 식품 포장 용기를 재활용한 후 발생하는 용출물 특성과 생물학적 안전성을 종 합적으로 평가하였다. PP/EVOH 식품 포장 용기 재활용 과정에서 발생하는 화학적 변화는 용출물 특성에 중요한 영 향을 미치며, 재활용 후 식품 포장 용기의 안전성을 저해할 수 있는 잠재적 위험 요소로 작용할 수 있음을 확인하였다. 본 연구는 재활용 식품 포장 용기 안전성 평가를 위한 기 초 자료를 제공하며, 향후 재활용 공정에서 화학적 안정성 과 생물학적 안전성 확보를 위한 보다 엄격한 기준 마련이 필요성을 제언한다.

This study investigates the increase in chemical leachates and the biological toxicity associated with repeated recycling of multilayer plastic food packaging composed of polypropylene (PP) and ethylene vinyl alcohol (EVOH). Based on the ISO 10993-5 cytotoxicity assay, a slight level of cytotoxicity was detected in the recycled samples, indicating a potential biological risk associated with the use of recycled materials. Chemical analyses using ICP, pH meter, balance, UV, UV/VIS spectrophotometer confirmed a cumulative increase in the total amount of leachates. Notably, the accumulation of heavy metals was identified in the recycled plastics, which was attributed to metal components originating from the shredding and reprocessing equipment used during recycling. SEM-EDX analysis further confirmed that the accumulated metals matched the elemental composition of the recycling equipment. These findings highlight the potential accumulation of heavy metals derived from processing machinery during the recycling of multilayer packaging and underscore the need for establishing safer and more controlled recycling systems.

자동차 부품으로 사용되는 air filter media인 PET와 frame으로 사용되는 PP의 혼합폐플라스틱의 제조공정의 edge scrap 및 부품의 교체로 발생된 post-consumer waste에 대한 재활용 연구를 진행하였다. 수거된 혼합 폐플라스틱을 파쇄 및 건조시킨 후 세 가지 형태의 상용화제의 배합비 별로 압출기를 이용한 용융 블렌딩을 실시하여 재생 칩을 제조하였다. 사용된 상용화제는 EVA, MBS, 그리고 가소화 재생 PVB이고, 이들의 배합비는 3~10wt.%까지 혼합하였다. 상용화제의 종류와 배합비의 변화에 따른 기계적 특성과 열적 특성을 비교하였다. 이들 상용화제 종류별 분석에서는 MBS 상용화제가 가장 뛰어난 기계적 특성을 보였고, 배합비는 3~5wt.%에서 우수한 특성 값들을 보였다. 또한 EVA를 상용화제로 사용한 경우 배합비가 3~5wt.%에서 내충격성 및 열적 특성의 향상을 보여 내충격성이 요구되는 재활용 제품으로의 응용이 기대된다. 재생 PVB수지를 상용화제로 사용한 경우는 전체적으로 특성치의 저하를 보이기는 하나 toughening effect가 요구되는 분야로의 응용이 기대된다.

Using the post-consumer waste and edge scrap mixed PET with small amount PP air filter elements of automobiles, It was studied that these mixed waste plastics of the various types of the PET were practicable for the material recycling. Various waste PET/PP plastics were collected, crushed, dried in vacuum, and extruded to recycled PET/PP chips. These chips were mixed with three kinds of compatibilizers, EVA, MBS, and recycled PVB of the ratio of 3~10wt.% for the purpose of the compatibility for the post-consumer waste and edge scrap. We investigated mechanical and thermal properties of PET/PP mixtures which were compounded with the weight ratio of compatibilizers. Compatibilizer, MBS application was showed the most excellent mechanical properties in the range of the 3~5wt.% EVA application was displayed good impact strength and thermal property in the range of 3~5wt.% Last, recycled PVB application was showed poor mechanical properties in the whole range ratio of the PVB.

본 연구는 재활용 PP/EVOH 기반 다층 시트에 SEBSg- MAH를 0, 10, 20 wt.% 첨가했을 때 미치는 영향을 종 합적으로 평가했다. 실험 결과, SEBS-g-MAH 함량이 증가함에 따라 OTR 및 WVTR이 유의미하게 감소하여 기체 및 수분 차단성이 향상됨을 확인했다. TEM 분석에서는 SEBS-g-MAH가 첨 가되지 않은 시편의 불균일한 EVOH 도메인이 SEBS-g-MAH 첨가 시 나노 수준으로 균일하게 분산되는 현상이 나타났다. FTIR 분석을 통해서는 SEBS-g-MAH가 첨가된 시편의 1735 cm1 부근에서 에스터 결합(C=O) 흡수 피크 가 뚜렷이 관찰되었다. 이는 SEBS-g-MAH의 말레산 무수 물(MAH) 작용기가 EVOH의 하이드록실기(-OH)와 화학적 으로 반응해 안정한 공유 결합을 형성했음을 입증한다. 이러한 결과는 SEBS-g-MAH의 양친매성(amphiphilic) 구조가 EVOH와의 화학적 상호작용과 PP와의 물리적 상호 작용을 통해 '분자적 교량(molecular bridge)' 역할을 수행했 기 때문으로 해석된다. 이로 인해 계면 안정화, 상 분리 억 제, 도메인 미세화가 이루어졌고, 결과적으로 복합계의 열 역학적 안정성 향상과 응력 전달 효율 증대를 가져왔다. 특 히 SEBS-g-MAH의 함량 증가는 계면 친화력 강화와 미세 구조 안정화를 촉진하여, 재활용 과정에서도 장기적인 산소 및 수분 차단 기능 유지를 가능하게 했다. 결론적으로, 본 연구는 SEBS-g-MAH가 재활용 PP/EVOH 시스템의 분산 상태 및 차단 성능을 개선할 수 있는 효과 적인 전략적 계면 개질제임을 명확히 제시한다. 이는 PP/ EVOH 재활용 포장재 개발에 있어 지속 가능한 고성능 소 재 솔루션으로서의 활용 가능성을 보여주는 중요한 근거가 될 것이다.

This study examines the influence of SEBS-g-MAH (styrene ethylene butadiene styrene grafted maleic anhydride) content (0, 10, and 20 wt%) on the oxygen and moisture barrier properties, as well as the morphological and chemical structural changes in multilayer plastics composed of recycled polypropylene (PP) and ethylene vinyl alcohol (EVOH). Oxygen transmission rate (OTR) and water vapor transmission rate (WVTR) analyses revealed a gradual decrease in permeability with increasing SEBS-g-MAH content, indicating improved barrier performance. Fourier-transform infrared (FTIR) spectroscopy confirmed the formation of ester bonds between the anhydride groups of SEBS-g-MAH and the hydroxyl groups of EVOH, as evidenced by a distinct absorption peak near 1735 cm⁻¹. This covalent interaction suggests enhanced interfacial compatibility. Transmission electron microscopy (TEM) revealed significant morphological evolution: without SEBS-g-MAH, EVOH domains were irregularly and coarsely dispersed within the PP matrix, whereas the addition of 10 wt% SEBS-g-MAH led to smaller domains and improved interfacial diffusion. At 20 wt%, the EVOH phase was finely and uniformly distributed, indicating stabilized phase morphology. These improvements in both chemical and morphological compatibility contributed to reduced interfacial tension, suppressed phase separation, and enhanced blend homogeneity. Overall, the results highlight the effectiveness of SEBS-g-MAH as a compatibilizer for recycled PP/EVOH plastics, providing a promising strategy for the development of sustainable, high-performance packaging materials.

수경재배한 파프리카 ‘시로코’ 온도조건 별(10℃ 와 20℃) 저장 시 PP필름의 개별 포장여부에 따른 생체중량 감소, 외관, 경도 등의 특성 변화를 조사하였다. 파프리카 생체중 량 감소 정도에서 포장 여부에 따른 차이가 커서, PP필름 개별 포장한 것이 무포장에 비해 중량감소 정도가 현저히 적었다. 무포장의 경우 온도에 따른 생체중량 차이를 보여 저장온도 10oC가 20oC보다 변화 폭이 적은 것으로 나타났 다. 가용성 고형물(SSC) 변화는 온도와 포장 여부에 따라 변화 패턴이 다르고 처리 효과도 저장 후기에 나타났다. 가 용성 고형물 함량은 저장온도 10℃ 에서의 필름 포장은 다 소 증가하는데 비해, 저장 20℃ 에서 무포장은 감소하였다. 파프리카 경도 차이도 저장 후기에 영향을 받는 것으로 나 타나 저장온도 20℃ 에서 무포장이 다른 처리에 비해 현저 히 낮았다. 그러나 같은 저장온도 20℃ 라도 필름 포장으로 경도 감소 정도 폭이 줄어드는 효과가 있었다. Hue angle 은 파프리카 ‘시로코’는 저장 중 감소하지만, 저장온도나 포 장여부가 영향을 미치는 것으로는 보이지 않았다. 외관에 따른 상품성은 저장온도 10℃ 에서 PP필름 포장을 통해 외 관에 따른 상품성이 다른 저장온도나 포장한 것보다 변화 폭이 적고, 상품성 보존에 매우 효과적인 것으로 나타났다. 파프리카 ‘시로코’ 외관 변화에서 보듯이 파프리카 선도를 보전하기 위해서는 적정한 온도 처리와 포장을 병행해야 수 확 후 상품성이 효율적으로 유지될 수 있을 것으로 판단된 다. 본 연구를 통한 파프리카 ‘시로코’ 저장온도와 포장여 부에 따른 연구 결과, 저장온도 10℃ 에서 포장 시 무포장 보다 외관적 선도 및 품질 유지에 도움이 되는 것으로 나 타났다. 본 연구에서 국내 유통환경은 파프리카 상품성이 보다 신선하게 유지될 수 있도록 포장이 필요하며, 앞으로 효과적 포장방법에 대한 연구가 지속적으로 이루어져야 할 것으로 보인다.

The aim of this study was to examine the effect of packaging on the quality maintenance of paprika (Capsicum annuum L. cv. Sirocco) stored at three different temperatures. Paprika was either unpacked (control) or packed with individual PP (propylene) film and stored at 10℃ and 20℃ for 30 days. Quality characteristics such as weight loss and appearance were examined. Paprika packed with PP film at 10oC showed fewer quality changes compared to unpacked paprika stored at the other temperatures. Commercial properties tended to decrease rapidly during storage at 20℃ with unpacked paprika. The degree of fresh weight loss was significantly lower in packed paprika at 10℃ compared to unpacked paprika stored at other temperatures. It was found that general appearance, soluble solids content, and hardness were complexly affected by storage temperature and PP film packaging. A storage temperature of 10℃ was effective in maintaining freshness, and paprika packed in PP film maintained greater freshness than unpacked paprika. Our results showed that packaging is necessary to preserve the freshness and improve the marketability of paprika in the domestic market.

자동차 산업의 발달과 함께 환경오염 문제가 심각해지면서 연간 300,000톤 이상 발생하는 폐타이어의 재활용에 대한 관심이 높아지고 있다. 본 연구에서는 폐타이어 재활용을 목적으로 40, 80, 140 mesh 크기의 폐타이어 분말을 선별한 후, 입도 분석을 통하여 크기를 확인하고 그 형상을 SEM을 통해 관찰하였다. 또한 각각의 폐타이어 분말을 Virgin PP와 혼합하고 Intermeshing CorotatingTwin Screw Extruder를 이용하여 TPV를 제조하고 특성 분석을 하였다. 이 중 효과가 좋은 140 mesh의 폐타이어 분말과Virgin PP, Waste PP, PP-g-MA 세 가지 종류의 매트릭스를 다양한 비율로 혼합하여 TPV를 제조한 후 UTM을 통한 인장강도, 연신율과 Izod impact로 충격강도 등을 측정하였고 TGA로 열안정성을 확인하였다. 또한 SEM을 통하여 폐타이어 분말의 분산정도및 파단면을 확인하였다.

300,000 tons of waste tires are annually being produced with development of the automotive industry in Korea. Landfill andincineration treatment system are causing the economic problem through secondary environmental pollution and waste. Therefore,as one of the ways to take advantage of this, Thermo-Plastic Vulcanized (TPV) composite was prepared by the groundwaste tire and plastic powders. The waste tire powder was gained by mechanical fracturing through crushers. The waste tire powderwas ground by a shear crushing method and a 2-stage disk mill method instead of cutting crushing one. The waste tire powderof 50 mesh was mixed with Polypropylene(PP) in various proportions. TPVs were prepared by an extrusion, and tensile andimpact tests were performed. In addition, the same experiments were repeated in 40, 80, 140 mesh conditions in order to observesize effect of waste tire powders.

미디어산업은 콘텐츠 시장과 광고시장의 이중적인 구조로서 전자가 제대로 작동하기 위해서는 후자의 원활한 작동이 필수불가결하나, 방송산업에 대한 기존의 연구들은 주로 콘텐츠와 시청자의 상호작용과 관련된 분야에 치우친 경향이 있다. 본 연구는 Fu의 PP모델을 중심으로 방송광고의 시청자 가치에 대한 새로운 분석을 시도하였다. 기존 연구에서 주로 사용하던 시청집단의 크기(시청률)나 인구사회학적 요소와 같은 1차원적 평가수준을 넘어, 해당 프로그램 시청집단의 구매력이나 구매동질성, 그리고 산업별 총이윤과 같은 광고주 시장성과와 직결되는 요소를 중심으로, 현재 국내 방송산업의 광고가격체계에 어떻게 반영되고 있는지를 탐색적으로 살펴보았다. 분석결과 현행 방송광고의 가격체계는 광고효율성의 평가에서 비합리적인 부분이 여전히 많은 것으로 나타났다.

This exploratory study is based on the PPM model (Fu, Li, & Wildman, 2005) which proposed a theoretical model for assessing the value of audience in television advertising. Korea has kept a unique advertising rate regulation for decades which basically determines advertising rate based on the time bracket and the size of the audience. By comparing the audience value based on PPM model and the advertising rate determined according to the policy, this study argues that it is time to reformulate the advertising regulation in Korea Overall the results suggest that the regulated ad pricing system, even though the policy makers claim that the current system reflects ‘market’, does not well reflect the economic logics underlying the PPM model. On the other hand, it was empirically shown that the public interest model of ad regulation is indeed serving the policy goals such as suppressing the programming of entertainment (as opposed to news and information) and narrowing the gap in terms of financial support between very popular and not so popular programs. We admit that a policy cannot serve all the desirable goals and sometimes a policy can bring about a positive consequence in certain area and at the same time harmful effect in others.

This paper suggests that there are two types of preposed PPs in English: locative PPs and subject PPs. This is on the basis of the syntactic patterns of preposed PPs in PP Subject Constructions. In explaining preposed PPs, locative PPs have subject and non⋅subject properties differently from subject PPs. I proposed that subject PPs are induced by syntactic EPP; however, locative PPs are motivated by discourse EPP. More precisely dual properties of locative PPs can be covered by assuming a new projection RefP(Referential Phrase) in terms of Split CPs, thereby extending Last Resort to Scope-discourse interpretive property in Rizzi(2004). This paper shows subject PPs occupy Spec TP and locative PPs occupy Spec RefP, and that the mixed properties of subject and non⋅subject that the preposed PPs display can be explained under (non)Specificity.

In order to commercialize large diameter PP pipes, the cutting work was attempted with the cutting machine(∅18″and AL120 cutter, 2100 r.p.m) used for the conventional PE or PVC pipe(∅1200 mm, t 70), but the cutting work was failed because the material of “PP pipe” melted and sticked to the surface of the wheel-cutter. In order to find the optimal structure and number of blades for wheel-cutters, an experimental investigation the temperature measurement of specimen and wheel-cutter and the visualization of cutted specimen surface and chip shape were carried out during and after experiment. In addition, modelings for cutting and heat transfer mechanisms have been developed for theoretical analysis. The theoretical and experimental results were in good agreement. The results show that the appropriate structure and the rotational speed of wheel-cutter are W60 and 650 rpm for the large diameter PP pipe cutting machine.

Recently, a Korean company succeeded in manufacturing ∅1500mm, t90 PP double wall pipe with ring stiffness ‘SN26’ for the first time in Korea. For commercialization, the developed productt must be cut to the required length with cutting machine in the continuous manufacturing process. The cutting operation was attempted with the cutting device(∅18″, 120P Wheelcutter for Aluminum, 2100rpm) used for the conventional PE or PVC pipe(∅1200mm, t70). In order to commercialize the developed product, product must be cut to the required length with cutting machine in the continuous manufacturing process. but the cutting operation was failed. The results of observation after processing, The material of the large diameter PP pipe was fused on the surface of the wheel cutter and the wheel cutter was detached. The purpose of this study is to research the effect of wheel cutter structure and rotational speed on cutting work when cutting large diameter PP pipes.

The use of hanging scaffolding for exterior wall painting and cleaning in building construction and maintenance carries the inherent risk of fall accidents. While periodic rope replacement is crucial for preventing accidents resulting from rope breakage, current regulations lack specificity in determining appropriate disposal period for fiber ropes. This study analyzed the tensile strength of the most commonly used PP fiber ropes with different diameters (16 mm, 20 mm) in the domestic construction industry. Additionally, the effect of outdoor exposure was examined by measuring the tensile strength of new ropes and ropes exposing to outdoor conditions for 30 days and 90 days. The results showed that the new ropes and those exposed to outdoor for 30 days met the KS (Korean Standards) criteria for tensile strength. However, a significant decrease in tensile strength was observed in ropes exposed to outdoor for 90 days compared to both the new ropes and those exposed for 30 days. Furthermore, the ropes exposed for 90 days did not meet the KS criteria. These findings indicate the degradation of PP fiber ropes due to UV (Ultra Violet) radiation, highlighting the importance of considering this factor when determining the replacement period for fiber ropes used in scaffolding work.

Wood-PP composite materials were prepared by Taguchi robust design method with L9 orthogonal array to optimize experimental conditions. Tensile strength of the composite materials was considered as the main properties. Amount of wood powder and modifier of resin were chosen as significant parameters. As the result of Taguchi analysis in this study, the amount of wood powder was the most influencing parameter on the increase of tensile strength. The optimal conditions were determined and these results were good agreement with data analyzed by Taguchi robust design method.

보호프로파일은(Protection Profile)은 특정형태의 제품군이 지녀야 할 보안 목적을 사용자 그룹에서 요구한 명세서이며 보호프로파일의 가정사항은 TOE(Target Of Evaluation)의 물리적, 인적, 네트워크적 관점을 포함하는 사용 환경과 TOE의 사용제한, 잠재적인 자산 가치, 추가적인 적용의 관점을 포함하는 TOE 사용 방법상의 내용을 기술한 것이다. 본 논문에서는 NSA(National Security Agency) 침입탐지 시스템 보호프로파일과 국가기관용 침입탐지 시스템 보호프로파일의 가정사항 항목을 비교 분석하였다.

A protection profile is the required specification document by consumer groups to specify what security purpose they would like to have in their specialized products. A protection profile assumption is the document that specifies consumer environment in the physical, artificial, network perspective and the contents of intended usage which include usage limitation, the value of latent asset, and additional applications for a TOE (Target of Evaluation). In this paper, we compare the assumptions of the NSA IDS PP and the IDS PP for government.

The lightweight foamed concrete specimens are made by mixing cement, gypsum, Manganese dioxide(MnO2), hydrogen peroxide, water, PP, Also, we study the physical and mechanical properties of lightweight formed concrete through diverse experiment which is to determine the optimal mixing proportion and require strength of the lightweight formed concrete. As a result of an experiment, Steel fiber is mixed, did not affect the strength, PP, increasing the amount of the compressive strength, flexural strength was increased.

In this paper, the mechanical properties according to the rCF weight percent(10, 20, 30, 40, 50wt%) of the rCFRP specimen were evaluated and analyzed. First, to prepare rCFRP specimens, pellets were prepared according to the type of weight percent, and rCFRP tensile specimens according to ASTM D638 were prepared using an injection molding machine. Tensile tests were performed on each of 10 specimens according to weight percent conditions, and tensile strength and modulus of elasticity were calculated. For a detailed analysis of the correlation between the internal structure of the specimen and the mechanical properties, the weight percent to the constituent materials of the rCFRP specimen was calculated using mCT and used for the analysis of mechanical properties. For a more detailed analysis, a detailed analysis of the mechanical properties of rCFRP was performed through the fracture surface analysis of the specimen using FE-SEM.