(1/14) So this is going to be my first true long post to Twitter and I am also covering the debate surrounding the banning of plastic straws. As such, I am rather nervous and I can only hope that this turns out alright! #StrawBan
(2/14) I want to focus on an alternative material used in drinking straws. This material is chitosan, which is also sold under the name of “REPA” amongst others. Chitosan is a biodegradable polymer made from renewable materials used to make flexible straws. #StrawBan
(3/14) Firstly, I shall cover the science. Chitosan is a modified form of chitin. Chitin is taken from renewable sources and deacetylated. This typically occurs through treating it with sodium hydroxide in an aqueous solution. #Chemistry #MaterialsScience 
(4/14) BENEFITS: Chitosan can be used to make straws virtually indistinguishable from typical non-biodegradable polypropylene drinking straws. Chitosan withstands temperatures from -200 °C to 140 °C and does not leach contaminants, making it suitable for all kinds of beverages.
(5/14) Another biodegradable material used in drinking straws is polylactic acid (PLA). This material does not degrade under landfill conditions, requiring instead to be sent for composting. In comparison, chitosan degrades to organic fertiliser 3 to 6 months after burial.
(6/14) Additionally, PLA is usually produced from grains and other edible crops. In contrast, chitosan is produced from the chitin in macerated shells, which form a natural waste product with few other uses.
(7/14) DRAWBACKS: I believe that the drawbacks of chitosan-based drinking straws can be divided into three categories:
-Cost
-Scalability
-Suitability
-Cost
-Scalability
-Suitability
(8/14) Cost: Straws made from chitosan are generally more expensive than their non-biodegradable non-renewable counterparts. However, the difference in prices between the two materials are not as high as I initially expected and could feasibly be balanced through various means.
(9/14) Scalability: While the shellfish exoskeleton feedstock is viable at the moment, it may limit the ability to match future demands. On the other hand, these shells are produced as a waste product of the fishing industry and so these could be reclaimed if demand was high.
(10/14) Suitability: As chitosan is ultimately produced from shellfish, I am not sure if this would conflict with some dietary laws. Furthermore, there is also the potential for chitosan to cause an allergic reaction in people with shellfish allergies.
(11/14) However, I do recognise that this is unlikely as shellfish allergies are caused by proteins that should be destroyed by the manufacturing process. Additionally, an early study has shown no evidence that chitosan-based products can cause an allergic reaction.
(12/14) In conclusion, chitosan-based drinking straws shows that alternative materials for flexible drinking materials exist that are both biodegradable and from renewable resources without sacrificing functionality as with other alternatives. #StrawBan
(13/14) Finally, the needs of disabled people must be prioritised and blanket bans of plastic straws without offering a suitable alternative are misguided and discriminatory. After all, what good is improving the world if everyone cannot enjoy it equally? #StrawBan
(14/14) If you would like to know any of the sources I used to compile this miniature essay then please just let me know and I will endeavour to help. Additionally, if you spot any inaccuracies then please just let me know and I will correct them as soon as possible!
@threadreaderapp Would you be able to unroll this please?
