• Textile Coloration and Finishing
• /
• v.34 no.3
• /
• pp.197-206
• /
• 2022

The purpose of this study was to confirm the optimal spinning conditions for PLA (Polylactic acid) as a fiber forming polymer. According to the melt spinning test results of PLA, the optimal spinning temperature was 258℃. However, it needs to note that relatively high pack pressure was required for spinning at 258℃. At an elevated temperature, 262℃, mono filament was broken easily due to hydrolysis of PLA at a higher temperature. In case of fiber strength, it was confirmed that the draw ratios of 2.7 to 3.3 were optimal for maximum strength of melt spun PLA. Above the draw ratio, 3.3, the strength of the PLA fibers was lowered. It was presumed that cleavage of the PLA polymer chain over maximum elongation. The heat setting temperature of GR (Godet roller) showed that the maximum strength of the PLA fibers was revealed around 100℃. The degree of crystallinity and the strength of the PLA fibers were decreased above 100℃. The optimal take-up speed (Spinning speed) was around 4,000m/min. Thermal analysis of PLA showed 170℃ and 57℃ as Tm (melting temperature) and Tg (glass transition temperature), respectively.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.8 no.2
• /
• pp.204-211
• /
• 2020

Poly-Lactic Acid(PLA) fiber is an eco-friendly material and is biodegradable, so it can be utilized for manufacturing porous construction materia ls with interna l pore connection. In this study, domestic PLA fiber products(0.5mm india meter, 1.0mm in length, 10mm in length) were tested for melting at high temperatures and high alkality, and they were incorporated with FA-based geopolymer. Compressive strength was obtained through high temperature curing and alkali activator, however the complete melting of the PLA fiber was not ensured. The previous study handling PLA fiber with 0.003mm in diameter was completely dissolved, but 0.5mm and 1.0mm in diameter showed 42.5% and 33.3% of dissolution ratio, respectively. In addition, the increasing fiber volume led floating fibers during curing, which had a negative effect on its workability and solubility. Although the properties of PLA fiber may vary depending on the raw materials and production conditions, PLA fiber with 0.1mm or less diameter is recommended for porous construction material.

• Composites Research
• /
• v.26 no.5
• /
• pp.273-278
• /
• 2013

PLA/PP polymer blends in various ratios (PLA:PP = 9:1, 4:1, 3:1, and 1:1), and their composites (PLA:PP = 1:1) with sisal fiber (10, 15 and 20 wt%) were fabricated using MAPP as compatibilizer. The aim of the work was to reduce the cost of biodegradable composites as well as to improve the impact strength of PLA using PP, a relatively cheaper thermoplastic. The developed composites were characterized for their morphological and mechanical properties. The tensile strength and modulus of the blends were decreased with increasing PP content whereas the strain at break and impact strength are increased. The tensile strength, modulus and water absorption were increased for hybrid composites with increasing fiber content.

• Proceedings of the Korean Fiber Society Conference
• /
• 2003.10b
• /
• pp.183-184
• /
• 2003

Poly(lactic acid) (PLA) is a highly versatile, biodegradable, aliphatic polyester derived from 100% renewable resources, such as corn and sugar beets. Because of the degradation mechanism, PLA is ideally suited for many applications in the environment where recovery of the product is not practical, such as agricultural mulch films and bags. Composting of post consumer PLA items is also a viable solution for many PLA products. (omitted)

• Proceedings of the Korean Society of Dyers and Finishers Conference
• /
• 2011.03a
• /
• pp.79-79
• /
• 2011

최근 플라스틱 제품의 사용후 폐기에서 발생 되는 환경적인 문제점들이 대두 되고 있는 가운데, 이러한 제품에 대한 친환경적인 재료 설계에 대한 요구가 거세지고 있는 실정으로 플라스틱 업계의 사활이 걸릴 정도의 중요한 문제로 부각되고 있다. 본 연구에서는 이러한 플라스틱 제품의 치명적인 환경적인 문제점을 극복하고자, Matrix 물질이 되는 플라스틱에서 부터 친 환경적인 생분해성 수지를 사용하면서, 물성의 강화제로써 천연물 유래의 여러 종류의 섬유를 사용하고자 하였다.가장 보편화된 생분해성 플라스틱인 지방족 폴리에스테르 계통의 생분해성 수지와 Polylactic acid에 대해 검토를 하였다. 지방족 폴리에스테르 의 경우는 기존 플라스틱 제품과 비교해서 유연하고, 신장율이 높고, PLA 대비 내열 사용한계 온도도 높아서 물성적인 측면에서 상당한 장점을 가지고는 있으나 가격이 매우 고가이므로, 기존 플라스틱을 대체하는 것에는 문제점이 있다. 반면 PLA의 경우 지방족 폴리에스테르 대비 절반 이하의 가격이고 기계적 강도 또한 매우 높기 때문에 기존의 플라스틱을 대체할 수 있는 가장 유력한 물질로 대두 되고 있으나, 사출물과 같은 충격이 요구되는 제품에 있어서는 PLA 고유의 약한 취성이 가장 큰 단점으로 지적되고 있다. 본 연구에서는 이러한 PLA를 기반으로 PLA의 장점이 기계적 강성을 유지하면서, 취성을 보완하기 위해 PBS를 혼합 할 수 있는 기술을 개발하였으며, 또한 원재료의 Cost를 줄이고, PBS 혼합에 따른 PLA의 기계적 강도 감소를 보완하기 위해 천연물 유래의 Wood fiber, Starch, Bamboo fiber, Cellulose fiber, Paper fiber 와 같은 각종 천연 Filler를 사용하여 기계적 기계적 강도 감소를 최소화 하였다.

• Proceedings of the Korean Fiber Society Conference
• /
• 2003.10a
• /
• pp.97-97
• /
• 2003

Recently, attention has been paid to biodegradable polymers in relation to the global environment. Poly-lactide (PLA) is one of such polymers and has studied by some investigators. In this study, the changes of crystal structure, crystal orientation and supermolecular structure of Poly(L-lactide) (PLLA) during drawing or annealing have been investigated.

• Composites Research
• /
• v.24 no.3
• /
• pp.1-5
• /
• 2011

Since the environmental problems and new stricter regulations are forcing the industries to introduce more ecological materials for their products, biodegradable materials have attracted increasing attention. Among these materials, Polylactic acid(PLA) is a promising candidate for its modulus, strength, chemical resistance. However, PLA could not be used for automobile industries for its low heat resistance and impact strength. In this study natural fibers were (jute fiber was) introduced as reinforcements in order to improve heat resistance and impact strength of PLA. Especially for improving the adhesion between PLA and jute, various surface treatments were tried. With each treatment, we verified that the impact strength of composite was improved. With annealing treatment, we found a remarkable increase of heat resistance of PLA composite.

• Proceedings of the Korean Fiber Society Conference
• /
• 2003.04a
• /
• pp.218-220
• /
• 2003

지방족 폴리에스터계 고분자인 폴리락타이드 (polylactide, PLA), 폴리글리콜라이드 (polyglycolide, PGA) 및 이들의 공중합체인 락타이드-글라이콜라이드 공중합체 (PLGA)는 생체 친화성이고 생분해성이며 물리적 강도가 우수하고 쉽게 성형할 수 있다. 그리고, 전기방사는 수 마이크로에서 수십 나노크기의 지름을 가지는 초극세 섬유인 나노섬유의 제조 기술로서 기존의 섬유 방사방식과는 근본적으로 다른 새로운 방사기술로 산업적인 융용 가능성이 무한한 미래지향적 기술로 최근 주목을 받고 있다. (중략)

• KIPS Transactions on Software and Data Engineering
• /
• v.11 no.12
• /
• pp.489-498
• /
• 2022

Recently, the textile industry, which is labor-intensive, is attempting to reduce process costs and optimize quality through artificial intelligence. However, the fiber spinning process has a high cost for data collection and lacks a systematic data collection and processing system, so the amount of accumulated data is small. In addition, data imbalance occurs by preferentially collecting only data with changes in specific variables according to the purpose of fiber spinning, and there is an error even between samples collected under the same fiber spinning conditions due to difference in the measurement environment of physical properties. If these data characteristics are not taken into account and used for AI models, problems such as overfitting and performance degradation may occur. Therefore, in this paper, we propose an outlier handling technique and data augmentation technique considering the characteristics of the spinning process data. And, by comparing it with the existing outlier handling technique and data augmentation technique, it is shown that the proposed technique is more suitable for spinning process data. In addition, by comparing the original data and the data processed with the proposed method to various models, it is shown that the performance of the tensile tenacity and elongation prediction model is improved in the models using the proposed methods compared to the models not using the proposed methods.

• Macromolecular Research
• /
• v.11 no.4
• /
• pp.207-223
• /
• 2003

For last five years, we are developing the novel local drug delivery devices using biodegradable polymers, especially polylactide (PLA) and poly(D,L-lactide-co-glycolide) (PLGA) due to its relatively good biocompatibility, easily controlled biodegradability, good processability and only FDA approved synthetic degradable polymers. The relationship between various kinds of drug [water soluble small molecule drugs: gentamicin sulfate (GS), fentanyl citrate (FC), BCNU, azidothymidine (AZT), pamidronate (ADP), $1,25(OH)_2$ vitamin $D_3$, water insoluble small molecule drugs: fentanyl, ipriflavone (IP) and nifedipine, and water soluble large peptide molecule drug: nerve growth factor (NGF), and Japanese encephalitis virus (JEV)], different types of geometrical devices [microspheres (MSs), microcapsule, nanoparticle, wafers, pellet, beads, multiple-layered beads, implants, fiber, scaffolds, and films], and pharmacological activity are proposed and discussed for the application of pharmaceutics and tissue engineering. Also, local drug delivery devices proposed in this work are introduced in view of preparation method, drug release behavior, biocompatibility, pharmacological effect, and animal studies. In conclusion, we can control the drug release profiles varying with the preparation, formulation and geometrical parameters. Moreover, any types of drug were successfully applicable to achieve linear sustained release from short period ($1{\sim}3$ days) to long period (over 2 months). It is very important to design a suitable formulation for the wanting period of bioactive molecules loaded in biodegradable polymers for the local delivery of drug. The drug release is affected by many factors such as hydrophilicity of drug, electric charge of drug, drug loading amount, polymer molecular weight, the monomer composition, the size of implants, the applied fabrication techniques, and so on. It is well known that the commercialization of new drug needs a lot of cost of money (average: over 10 million US dollar per one drug) and time (average: above 9 years) whereas the development of DDS and high effective generic drug might be need relatively low investment with a short time period. Also, one core technology of DDS can be applicable to many drugs for the market needs. From these reasons, the DDS research on potent generic drugs might be suitable for less risk and high return.