# Sustainable Materials from Waste Paper: Thermal and Acoustical Characterization
## 1 Introduction
### Paper Waste  
Paper is a material of ancient and natural origin, dating back to 105 AD [14; 15], and is mainly composed of cellulose fiber, the most common natural polymer and one that is inexhaustible on the globe. Several products are manufactured by the paper industry, such as printing paper, sanitary papers, newspaper and packaging products. Moreover, a great number of applications in the architectural field exist including those made of paperboard, corrugated cardboard, honeycomb panels and paper tubes [16]. Different researchers have tested the properties of paper waste-based components presenting the potential of using the waste paper, the physical properties of cellulose insulation and the environmental factors that affect these properties [17; 18; 19; 20; 21; 22; 23; 24]. [PERSON] et al. [17] carried out a study investigating the physical and mechanical properties, ultrasound pulse velocity, and thermal and structural performance of waste paper aggregates mixed with lime, and found that the thermal conductivity varied between 0.097 W\(\cdot\)m\({}^{-1}\cdot\)K\({}^{-1}\) and 0.12 W\(\cdot\)m\({}^{-1}\cdot\)K\({}^{-1}\). [PERSON] et al. [19] added cotton waste to fired bricks with paper mill waste and cement binder as developed by [PERSON] et al. [18], achieving a great compressive strength and thermal conductivity ranging from 0.25 to 0.32 W\(\cdot\)m\({}^{-1}\cdot\)K\({}^{-1}\). [PERSON] et al. (2020) examined the properties of cellulose fibers sourced from paper and cardboard waste, testing a thermal conductivity of 0.042 W\(\cdot\)m\({}^{-1}\cdot\)K\({}^{-1}\). [PERSON] (2018) studied the effects produced by the addition of waste paper to clay bricks, focusing on the thermal and mechanical behavior. The results showed that these bricks have values of compressive strength lower than 0.45 MPa and a thermal conductivity lower than 0.1 W\(\cdot\)m\({}^{-1}\cdot\)K\({}^{-1}\), allowing their use for thermal insulation. [PERSON] et al. (2019) combined waste from newsprint paper with perlite and plaster on a cane body. Different combinations of raw materials were tested, demonstrating that samples produced with a double row of canes had the lowest thermal conductivity and ultra-sound permeability coefficients. [PERSON] et al. (2019) developed bricks with a mixture of sawdust, waste paper aggregates from recycled newspapers and lime-based binders, showing that the addition of sawdust caused very low values of thermal conductivity (0.046-0.069 W\(\cdot\)m\({}^{-1}\cdot\)K\({}^{-1}\)). [PERSON] et al. (2019) investigated the use of the hot-compression method in order to avoid the formation of microbes and fungi on three different cellulosic panels derived by the post-consumer coffee industry (jute textile, paper cups and coffee grounds) suitable as insulators. [PERSON] (2018) carried out a comparison in terms of embodied energy per kg between cellulose and other insulation materials, demonstrating that the cellulose-based products had the lowest range, from 0.94 to 3.33 MJ/kg, comparable to cork (4 MJ/kg). [PERSON] et al. (2019) investigated the acoustic properties of some materials, such as cardboard, by means of the impedance tube. They found that they are suitable for building acoustic panels. [PERSON] et al. (2019) studied some panels, overlapping corrugated cardboard panels from the packaging industry. They found that the panels presented promising acoustic insulation performance in terms of transmission loss, although not in terms of sound absorption coefficients. According to [PERSON] et al. (2020) the absorption coefficient of a sound absorber produced using cellulose was 0.75, which was lower than that of glass wool but higher than that of polyester. Paper Waste Trend Production in Italy and Apulia  
In Italy, wastes are categorized as either municipal or special waste, and further as hazardous or non-hazardous according to their riskiness. Paper waste belongs to the municipal category.