본 연구는 poly-lactic acid(PLA)에 충전제로 radiata pine 목분(RDP), 활엽수 잡목 목분(MIX), 편백 수피(CYP-B),

치수안정화제로 피마자왁스(HCO), 계면결합제로 CYP-B, 단백질 함량이 약 40%를 차지하는 동애등에 분말(black

soldier fly, BSF) 그리고 BSF-기반 접착제(PAR)를 첨가하여 제조한 bio-composites의 휨강도, 수분흡수율(MAR), 길이

선열팽창계수(LCTE), 부피팽윤율(TVS)에 미치는 인자의 분석을 통하여 최적 제조 조건을 제시하고자 수행하였다. 사

출용 PLA(PLA-1)에 충전제로 RDP, MIX, CYP-B를 혼합하여 제조한 composites(PLA-1/RDP, MIX, CYP-B)의 휨강

도는 RDP 또는 CYP-B로 제조한 composites에서 높았다. 수분 흡착에 의한 치수 변화를 억제하기 위하여 치수안정화

제로 사용된 HCO의 적용량 증가(2.5 wt%에서 5wt%)는 PLA-1/CYP-B의 휨강도를 증가시켰다. PLA-1/RDP의 휨강

도는 CYP-B, PAR을 계면결합제로 적용하여 제조한 composites에서 높았으며, LCTE는 PAR로 제조한 compo sites에서

가장 낮았다. MAR는 PLA-1/RDP에서 계면결합제별 차이가 없었으나, PLA-1/MIX에서 목재-플라스틱 복합재(wood-plastic

composites, WPC) 생산에 있어 계면결합제로 사용되고 있는 maleic anhydride(MAA)보다 CYP-B가 효과적인 것으로

조사되었다. Composites 제조에 있어 PLA-1 및 충전제의 배합비와 상관없이 PLA-1/CYP-B의 휨강도, MAR, LCTE는

PLA-1/RDP 및 PLA-1/MIX보다 우수하였다. 특히 50 wt% PLA-1/40 wt% CYP-B에서 계면결합제로서 5 wt% PAR의 적

용으로 대부분의 물성은 개선되었다. 결과를 종합하면, 50 wt% PLA-1에 40 wt% CYP-B, 5 wt% HCO 그리고 5 wt%

PAR가 composites 제조를 위한 최적의 배합 조건으로 조사되었다. 이 조건으로 제조한 PLA-기반 composites는 국립

산림과학원에서 고시한 WPC의 폼알데하이드 방산량(<1.5 mg/L) 및 LCTE(<6.0×10-5/℃) 기준을 만족하였으며, 휨강

도 및 MAR는 5wt% MAA로 제조한 composites보다 우수하였다. 따라서 WPC 기준에서 요구되는 추가 항목에 대한

품질 기준을 만족할 경우 다양한 용도의 생분해성 플라스틱 소재로 활용이 가능할 것으로 기대된다. 또한 인체 및 환

경 유해성이 있는 고가의 합성 계면결합제인 MAA에 대한 무독성의 단백질-기반 계면결합제의 대체 가능성을 제시하

였으며, CYP-B를 composites 제조용 충전제로 활용함으로써 폐기물의 재자원화로 환경적인 측면에서 다양한 편익을

제공할 것으로 예상된다.

In this study, PLA-based bio-composites were fabricated with lignocellulosic filler (RDP, MIX or CYP-B),

hydrogenated castor wax (HCO) as a dimensional stabilizer and CYP-B, BSF, which contains about 40% protein, or

proteinaceous adhesive resin (PAR) formulated with hydrolyzates of BSF as an interfacial binder. The optimal fabricating

conditions were determined by investigating the impact of various factors on the bending strength, MAR, LCTE and TVS of

the bio-composites. Bending strength of each composite, fabricated with injection-grade PLA (PLA-1), with either RDP

or CYP-B was higher than that with PLA-1 and MIX. When the content of HCO, which was used to suppress dimensional

changes caused by a moisture absorption, increased from 2.5 wt% to 5 wt%, the bending strength of PLA-1/CYP-B

increased significantly. The highest bending strength and the lowest LCTE were found in the PLA-1/RDP fabricated

with CYP-B and PAR. MAR of the PLA-1/RDP was not affected by the type of interfacial binder, but CYP-B was found

to be more effective than MAA, which is extensively used in the production of WPC, in PLA-1/MIX. The bending

strength, MAR and LCTE of PLA-1/CYP-B on all weight ratios of PLA-1 to filler were superior to those of PLA-1/RDP

and PLA-1/MIX. Particularly, 50 wt% PLA-1/40 wt% CYP-B added with 5 wt% PAR showed higher performances than

those with any other weight ratio. Composites fabricated with 50 wt% PLA-1, 40 wt% CYP-B, 5 wt% HCO and 5 wt% PAR

met the LCTE (<6.0×10-5/℃) and formaldehyde emission (<1.5 mg/L) standards designated by the National Institute of

Forest Science (NIFOS), and exhibited higher bending strength and MAR than those with 5 wt% MAA. The composites

are expected to use as biodegradable plastic materials for various applications, satisfying other specifications in the

NIFOS’s WPC standard. In addition, this study demonstrated the feasibility of replacing MAA, which is both expensive

and poses human health and environmental risks, with a non-toxic PAR. Furthermore, the use of CYP-B as a filler in the

production of bio-composites enables waste recycling and is expected to provide a wide range of environmental benefits.

Bio-composites, Interfacial binder, Proteinaceous adhesives, Poly(lactic acid), Wood/wood bark flour

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