S. Basu, S. Malik, G. Joshi et al.
Carbohydrate Polymer Technologies and Applications 2 (2021) 100050
Table 1 Common bio-additives used for different grade for papers.
Bio-additive
Type of Pulp/ Paper
Reference
Cationic cellulose
Gao et al., 2016 ; Rana et al., 2021
- Bleached chemithermo-mechanical pulp (BCTMP) - Recycled pulp - Unbleached wheat straw soda pulp - Unbleached bagasse soda pulp
Carboxymethyl cellulose
Strand et al., 2017 ; Tarrés et al., 2018
- Bleached softwood kraft pulp - Recycled cardboard boxes pulp
Cellulose nanofibers
Tarrés et al., 2018 ; Delgado Aguilar et al., 2015 ; Espinosa et al., 2015; Jin, Tang, Liu, Wang & Ye, 2021
- Recycled cardboard boxes pulp - Bleached kraft hardwood pulp (BKHP) - Semichemical wheat straw pulp - Food packaging paper
Ulbrich et al., 2012 ; Strand et al., 2017 ; Hamzeh, Ashori, Khorasani, Abdulkhani & Abyaz, 2013
Cationic starch
- Bleached softwood pulp with pine/spruce ratio 70:30 - Bleached softwood kraft pulp - Bleached bagasse soda pulp
Hemicelluloses
Lima et al., 2003
- Sulphate kraft pulp - Eucalyptus kraft pulp
Hamzeh et al., 2013 ; Bhardwaj et al., 2016
Chitosan
- Bleached bagasse soda pulp - Old corrugated containers (OCC) recycled pulp
Carrageenan
Liu et al., 2017
- Bleached pinewood kraft pulp
Salam et al., 2015 ; Cheng et al., 2017
Proteins (soy, cottonseed)
- OCC, Neutral sulphite semichemical pulp (NSSC), Virgin kraft pulp - Whatman paper, speciality paper
Guar gum
Dasgupta, 1999
- Tissue Paper
been in focus owing to environmental intendancy measures. The loss in strength properties by recycling of fibre is ascribed to its repetitive drying phase, which results in irreversible hornification of the fibres. Since, the hornified fibres fail to achieve their actual configuration com- parable to its virgin state, the inter-fibre bonding (interaction of func- tional bonding groups like carboxyl, hydroxyl and carbonyl) is largely affected ( Fernandes Diniz, Gil & Castro, 2004 ; Hubbe, Venditti & Rojas, 2007 ; Minor & Atalla, 1992 ; Nazhad & Sodtivarakul, 2004 ). A num- ber of chemicals are used in the manufacturing of paper sheets and paper-based products to abridge these gaps in recycled fibres and also enhance the performances of virgin fibres. These chemical additives are employed to engineer conventional paper properties like strength, print- ability, opacity and brightness. Besides these features, additives can con- fer special attributes to paper based cellulosic fibres such as gas barrier, magnetic properties, superhydrophobicity, flame retardancy, electrical conductivity, photocatalytic activity etc. ( Arbatan, Zhang, Fang & Shen, 2012 ; Lahtinen, Nättine & Vartiainen, 2009 ; Shen, Song, Qian & Ni, 2011 ). However, paper mill effluents comprise of these chemical addi- tives and happen to be detrimental to living forms since they can dis- turb the overall systemic behaviour in species. Moreover, such effluents often result in oxygen depletion of water bodies and the aquatic organ- isms are posed with alarming threats of anoxia ( Bijan & Mohseni, 2004 ; Kim Oanh et al., 1999 ; Lacorte et al., 2003 ; Thacker, Nitnaware, Das & Devotta, 2007 ). Hence, more sustainable additives can be selected on the basis of relevant criteria including low toxicity, compatibility with the host material, retention capability and expense. The application of bio-polymers has been a successful method to minimize the risk of envi- ronmental abasement and enhance the strength properties of cellulosic fibre networks in paper production ( Fatehi, Qian, Kititerakun, Rirksom- boon & Xiao, 2009 ). Natural polymers like starch (cationic, anionic, ox- idized starch etc.) ( Johansson, Lundström, Norgren & Wågberg, 2009 ; Lindström, Fellers, Ankerfors & Nordmark, 2016 ; Shen et al., 2014 ), gums ( Lee, Lee & Youn, 2005 ; Lima, Oliveira & Buckeridge, 2003 ), car-
rageenan ( Liu, Li & Xie, 2017 ), soy protein ( Salam, Lucia & Jameel, 2015 ), crop grain based gluten ( Andersson, 2008 ; Guazzotti, Marti, Pier- giovanni & Limbo, 2014 ), molasses ( Fahmy, 2014 ), cellulose deriva- tives ( Fatehi et al., 2009 ; Lindström et al., 2016 ; Shen et al., 2014 ), chitosans ( Balan, Guezennec, Nicu, Ciolacu & Bobu, 2015 ), alginates ( Andersson, 2008 ) etc. serve as additives in paper production to ad- dress diverse functions starting from strength addition to coating, sizing agents to retention aids ( Andersson, 2008 ; Ren, Peng, Peng & Sun, 2011 ; Zakraj š ek & Golob, 2009 ). Table 1 represents the application of some common bio additives for their use in diffeent type of pulp and paper manufacturing. Nature of charge on the biopolymers or their derivatives further in- fluence the interactive behaviour with negatively charged paper furnish. Anionic biopolymers do not readily interact in bonding as the paper furnish is itself anionic in nature. Anionic biopolymer requires an ad- ditional cationic unit such as alum which act as an intermediate for their ability to enhance fibre bonding. In case of anionic biopolymer, the concentration of alum and pH (4.2–4.7) of the system plays a vital role in retention and adsorption of the biopolymer. The use of cationic and anionic biopolymer together provides flexibility in use of anionic biopolymers as the need of alum is eliminated in this case. The anionic biopolymer should be added first followed by the cationic biopolymer in the system for avoiding the system shear. Photographic grade paper is one such example of combination of anionic and cationic polymer ( Gao, Li, Shi & Cha, 2016 ; Read, 1983 ). The surface charge density of a biopolymer could reverse after cationic or anionic modification. The surface charge density of cationic modified cellulose increases in comparison to unmodified cellulose fi- bres. However, it was much greater in case of cationic starch. The addi- tion of cationic modified biopolymer could decrease the zeta potential because of existing positive charge. On the other hand, the zeta potential of pulp suspension increases on addition of anionic modified biopolymer ( Gao et al., 2016 ; Read, 1983 ).
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