## 1 Introduction  
The exceptional properties in natural-fiber-reinforced composites include the high strength-to-weight ratio, improved durability, and design flexibility [1]. This has resulted in the increasing interest in natural-fiber-reinforced composites due to the increase in demand for sustainable and eco-friendly materials [2; 3]. Hemp fiber (HF) has emerged as one of the potential reinforcing fibers for polymer composites among various natural fibers based on its properties and ecology [3]. Hemp fiber has a greater cellulose content (70-90%) than that of other natural fibers such as SSI, jute, and flax [4; 5]. It has a high cellulose content and, therefore, a high modulus and tensile strength of the fiber in mechanical performance [6]. Moreover, HF exhibits a low density (1.48 g/cm\({}^{3}\)), which renders HF appropriate for lightweight composite applications [3]. The high strength and low density are suitable for gaining a better specific strength than other conventional reinforcements like glass fiber [7]. Although HF has favorable features for use, its hydrophilic property makes it difficult to serve as reinforcement in hydrophobic polymer matrices [5]. This disparity in surface energy between the fiber and matrix results in weak interfacial bonding which may also restrict the ability of stress transmission and composite mechanical performance [8]. In response to this problem, numerous surface modification strategies have been developed to improve the compatibility and interfacial bonding of HF with polymer matrices. Of these surface modification methods, plasma treatment has received considerable interest owing to its eco-friendliness, efficiency, and versatility [9]. Instead of chemical methods, plasma treatment has advantages such as the fact that it consumes less time than chemical methods, is low-energy, and causes less environmental impact [10]. Dielectric barrier discharge (DBD) plasma, a type of atmospheric plasma, is an especially attractive plasma technology for the continuous processing of fibers and for scalability towards industrial usage [11]. Plasma technology can produce a series of cleaning, etching, polymerization, and crosslinking effects, as well as other complex physical and chemical effects [12]. Plasma treatment leads to diverse changes in the surface of fibers like adding groups and enhancing roughness for better wettability [13; 14]. These alterations occur due to the interactions between reactive plasma species and the fiber surface in a manner with factors, like the power level and treatment duration affecting the type and degree of modification. Introducing groups like carbonyls, carboxyl, and hydroxyls onto the surface of fibers through plasma treatment boosts the compatibility and reactivity with the polymer matrix [14]. These functional groups are able to engage in chemical bonding with the matrix which enhances adhesion [15]. Additionally, the increase in surface roughness caused by plasma etching results in a surface area for interlocking between the fiber and matrix [13]. Prior research has shown that using plasma treatment can enhance the strength of composites made from fibers [13; 16]. However, there is a need for an investigation into how to best optimize DBD plasma parameters for surface modification in HF applications specifically. The interplay between plasma treatment effects on HF surfaces and how this impacts the properties of HF-reinforced composites is essential for creating eco-friendly composite materials, with high performance capabilities. However, the utilization of plasma to process hemp fibers is relatively unstudied, especially considering how plasma affects various constituents like hemicelluloses and lignin. Ramie fibers are the subject of the most research on lignocellulosic fibers and the potential for plasma treatment of these fibers. [PERSON] et al.