Evaluating the performance of hemp bast fibres in the production of packaging paper using different …
on the fibrillation of the fibres was assessed. Additionally, the drawbacks of using wastepaper during pulp preparation and the benefits of using hemp bast fibres pulp were demonstrated through pulp blending trials (hemp pulp and wastepaper pulp). These studies can contribute to the paper production industry, particularly in our country where it is based on the usage of wastepaper. The blending study results can be used to meet market demands for paper mills in terms of paper grade and required quality by suggesting that the degradation in recovered material quality may be compensated by blending with virgin material or that low cost may be obtained by blending the virgin source with the recovered source. This study is aimed at providing information to wood-based or wastepaper-based mills that lack wood-based pulp but are located in areas with non-wood fibre sources that are readily available. It also aims at demonstrating the feasibility of incorporating a non-wood pulping line to meet fibre demands. Materials and methods Commercial-grade hemp bast fibres were obtained from a hardware store. Wastepaper with the CEPI grade number ‘ 1.04.00 ’ was randomly selected from the wastepaper stockpile of ‘Selkasan Kağı t ve Paketleme Malzemeleri A.Ş. -Turkey ’ . Glycerine with a purity of 86.5% used during microscope imaging was supplied from Frank P-TI GmbH, Germany. Tap water was used as a fibre- -waster suspension preparation aid and diluent. In this study, the preparation of hemp bast fibre pulps was divided into three steps (size reduction, kraft pulping and beating). Subsequently, hemp bast fibre and wastepaper handsheets were prepared by increasing the hemp bast fibre ratio from 0% to 100% and decreasing the ratio of wastepaper by 20%, along with the preparation of wastepaper pulps. Additionally, certain analyses were performed to determine the properties of cooked and beaten hemp bast fibres (fibre morphology, crystallinity and chemical changes). Finally, paper strength tests were run on the handsheets prepared according to the blending plan. According to the fibre classification results of Tutuş et al. [2016], hemp bast fibre pulps are among the long-fibred pulps. The size of the hemp bast fibres must be reduced before processes to prevent clumping. A fine cutting mill (NETZSCH, model type: CS-Z) was used to size-reduce the hemp bast fibres to 4 mm (processed twice). The size-reduced hemp bast fibres are denoted as ‘ raw hemp bast fibres ’ from this point forward. In this study, two batches of hemp bast fibre pulps were produced under the same conditions. The batches were cooked (pulping) in a batch digester, which rotates four times in one minute and has temperature control capabilities. For each batch, 500 g of oven- dry raw hemp bast fibres were charged into the digester. The conditions selected for kraft pulping are given in Table 1.
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