**2. Material and methods**

*Textile Industry and Environment*

affect up to 25% waste ratio [17, 18].

tions from recycled products [28].

Taguchi OA experimental design. They have used blend ratios, blending technique, cylinder speed, and rotor speed as predictors. They have collected flat strips from carding machines and recycled them. Besides, comber noils, untwisted roving wastes, and Pneumafil wastes were directly used. They have produced virgin cotton/spinning waste blended yarns with two different levels of blend proportion (17/83 and 33/67) for both blowroom blending and draw frame blending. Their model showed that blend ratio and rotor speed are the most influencing factors for yarn quality. Reducing rotor speed improved the yarn evenness, imperfections, and strength. Yarn strength was found lower with draw frame blending, but on the other hand with this blending type, high portion waste containing yarns' evenness, imperfection, and elongation values are better than blowroom blending [26].

Halimi et al. investigated the effect of waste ratio (0, 12.5, 25, 37.5, 50, 62.5, 75, and 100%) and spinning parameters (rotor type, rotor speed, and opening roller speed) on the rotor yarn quality. Cotton wastes were collected from openingcleaning machines and cards processed to reduce impurities. Greek cotton was chosen due to the suitable fiber length for blending with recovered fibers. They have reported that yarn appearance, level of irregularity, and the yarn uniformity did not

Celep et al. investigated the thermal comfort properties of the single jersey fabrics produced from virgin/recycled cotton fiber-blended open-end rotor yarns (100/0, 50/50, and 0/100). Recycled cotton fibers were obtained from fabric scraps from garment industry. They have found that fabrics containing recycled cotton fibers show higher thermal resistance and lower thermal conductivity, thermal absorptivity, and air permeability and give a warmer feeling at first touch [27].

Recycled denim fabrics by using recycled cotton fibers (varying from 30 to 85% blend ratio), recycled PES fibers, Tencel fibers, and virgin cotton fibers were produced. They have found that recycled fiber-blended yarns have higher unevenness, IPI faults, and hairiness comparing to the standard yarns, resulting with noticeable nubs in fabric surface. This case did not affect fabrics' physical and mechanical properties significantly but provides better abrasion resistance contrary to expecta-

Yılmaz et al. have focused on the effects of different waste cotton fiber types and the amount of waste in the blends (varying from 5 to 40%), on the quality of conventional ring and OE-rotor yarns. They have used preparation process wastes (blowroom and carding) and Pneumafil wastes (sucked on the draw frame, roving frame, and conventional ring spinning machines). They have found both for conventional ring-spun and OE-rotor yarns that the blends containing pneumafil wastes resulted with better yarn properties, while the blends with blowroom and flat wastes caused worse yarn qualities. In general, flat waste fiber blends have higher neps and hairiness values. They have concluded that when the waste percentage was increased from 5 to 40%, yarn irregularity values increased up to 37 and 16%, yarn hairiness increased by about 21–22%, yarn tenacity values decreased by 22, and 52%, breaking elongation decreased by 7 and 38%, for ring-spun and rotor yarns, respectively. As expected, with the usage of waste fiber, the most deteriorated yarn properties were yarn unevenness in conventional ring-spun yarns and tensile properties in rotor yarns. Their findings showed that the effect of waste fiber usage on knitted fabrics' pilling behavior was significant and Pneumafil fiber blends increased the pilling

resistance, while for other waste fiber blends, on the contrary [29].

Béchir et al. evaluated the effect of recycled fiber ratio and number of recycling passages on the yarn quality and predicted the quality of the blend using a mathematical approach. They have concluded that recycling process of cotton waste with four passages gave an optimal global quality of fibers. Unevenness and IPI values of blended yarns increased with the increasing of recycled fiber ratio in the yarn [30].

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The main objective of this study is filling the gap in the literature via investigating the properties of the yarns produced with cotton wastes, generated in different sources. For this purpose, different waste types (card waste, blowroom waste, sliver waste, and recycled cotton fiber from ecru fabric waste) and waste ratios (10/90, 30/70, and 50/50) were used in rotor spinning. As a pre-treatment and recycling process, all waste types were processes in Micro Dust and Trash Analyzer (MDTA) in two passages. Simultaneously, trash and fiber content of these wastes were analyzed, and the fiber length specifications of wastes after recycling process were evaluated by length control tester (Textechno). Length control tester is a mobile device for use in the spinning mill, developed for the measurement of fiber length parameters on slivers or cotton in tuft form. The test results of length control tester give information about the mechanical stresses which the fibers undergo in the manufacturing process and optimum settings of card, draw frame, or combing machines [34]. Besides, fiber contents of the wastes were analyzed with MDTA, and test results are given in **Table 1**. Trash analysis of the virgin cotton was performed from sliver form, resulting with high ratio of fiber content. Subsequently, wastes were blended with virgin cotton fibers (in sliver form) with the same machine. Then, Ne 20/1 open-end yarns were spun by using these slivers on Rieter open-end machine (R40). Single jersey fabrics were knitted by using Mesdan Lab Knitter with the same tightness factors under constant machine settings.


*\*is corresponding to the test result given in brackets.*

#### **Table 1.** *Fiber specifications.*

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The standards of yarn and fabric tests applied were given below:


The effect of waste type and blend ratio on the physical and mechanical properties of the yarns and the fabrics, produced with virgin/waste cotton fibers, were statistically analyzed by using SPSS.
