No abstract

In this study, the effect of alkyl ketene dimer (AKD) on the mechanical and physical properties of natural fiber (NF) and glass fiber (GF) reinforced poly(lactic acid) (PLA) composites were investigated in detail. The hybrid PLA composites were manufactured by extrusion method followed by hot press molding. AKD was used to improve the hydrophobicity of hybrid PLA composites and compatibility of NF and PLA in the polymer matrix. The tensile and flexural tests, thickness swelling, water absorption, and contact angle measurements were accomplished for determining the performance of the hybrid PLA composites. The surface morphology of the hybrid PLA composites was also performed by scanning electron microscopy. The incorporation of AKD and NF into PLA matrix improved the mechanical strengths by 40% and above compared to those of samples without AKD. But, tensile and flexural moduli decreased as 7% and 14% of the samples with NF and AKD, respectively. Contact angle was higher for the hybrid PLA composites with AKD compared with the composites without AKD. However, the results revealed that in the presence of GF, AKD had no significant effect on overall properties of the hybrid PLA composites. In the light of the findings, AKD may have a potential usage as coupling agent in the NF filled PLA composites.

Özet: İğne yapraklı ağaçlardan farklı tekniklerle üretilen doğal çam reçinesi, oldukça kıymetli ve kadim bir silvikimyasal üründür. Başta kimya sanayi olmak üzere, kağıt, yol boyası, plastik sanayi, tıp ve kozmetikte sayısız kullanımı mevcuttur. Doğal çam reçinesinin üç kaynağı bulunmaktadır. Bunlar; 1) çam ağacı reçinesi 2) sülfat reçinesi 3) ekstrakt reçinesidir. Son yıllarda bütün dünyada sentetik reçine tüketimine getirilen yasal kısıtlamalar sektörü zorunlu olarak biyobozunur ürünlere yönlendirmektedir. Türkiye'de reçine üretimine uygun kızılçam ormanları olmasına rağmen, bugün ticari anlamda doğal ham reçine üretimi ve bu konu üzerine bilimsel çalışmalar istenilen düzeyde değildir. Bu çalışmanın amacı, farklı çözücü türlerinin çam kökü ekstraksiyon reçinesinin verimi ve kimyasal özellikleri üzerine etkisini incelemektir. Analizler sonucunda ekstraksiyon verimleri %16 ile %22 arasında bulunmuş olup en yüksek verim alkol-benzen çözücü sisteminde elde edilmiştir. Verime paralel şekilde, en yüksek asit ve sabunlaşma sayıları da alkol-benzen kullanılan örneklerde sırasıyla 174,87 ve 180,33 mgKOH/g bulunmuştur. Milli kaynaklarımızın ve ekstraksiyon reçinesi üretimindeki mevcut potansiyelimizin değerlendirilmesi için doğal reçinenin verimini ve kalitesini etkileyen fiziksel ve kimyasal faktörler üzerine daha detaylı ve etkin çalışmalar yürütülmesi gerekmektedir.

Polyurethane foams are used in many different applications, such as insulation and coating materials, packaging, furniture and so on. It has very low weight, low cost and thermal conductivity hereby frequently preferred by architectural and construction industry. On the other hand, these large-scale uses bring with waste problem after applications. In this study, the effect of polyurethane foam waste (PUw) on the thermal and morphological properties of polypropylene (PP)/ poly(lactic acid) (PLA) composites plasticized with polyethylene glycol (PEG 400) was investigated. PUw filled PP/PLA composites were prepared using melt blending followed by compression molding.Thermal and morphological properties of PUw filled PP/PLA composites were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), thermal conductivity analyzer and scanning electron microscopy (SEM). The results shown that the thermal conductivity of the composites improved significantly with addition of PUw, while glass transition temperature (Tg), the melting temperature (Tm) and melting enthalpy (ΔHm) values of the composites decreased. Based on finding, the PUw could be used as filler in PP/PLA composites for insulation and energy efficiency.

This study's objective was to investigate lean manufacturing knowledge, awareness, and integration maturity in one of Türkiye's most significant furniture manufacturer clusters and discover the extent of tapped and untapped potential offered by lean manufacturing for the furniture industry. This study developed a survey-based data collection methodology consisting of five sections with different features. Seventy-five small to large enterprises were invited to participate in the study. Out of seventy-five, twenty-seven furniture manufacturers participated in the study. The study revealed that lean manufacturing awareness and integration maturity vary significantly. This variation could prove lean manufacturing is still far from becoming a mainstream modern management technique for members of the furniture manufacturing cluster in Bursa, Türkiye. According to 92.59% of the study participants, reducing manufacturing costs is the most common internal motivation that either triggered or has the potential to trigger lean manufacturing integration. Moreover, the amount of investment required (66.67%) to deploy lean manufacturing is the primary barrier encountered by the organizations, followed by a lack of training opportunities for workers with a percentage of 62.96%. This study was expected to serve as a valuable resource for academics and professionals intrigued by the extent of the relationship between lean manufacturing and Turkish furniture industry members.