remember those plastic sheet, are already cut into strips and braided together and netting and rope are already made by the people in need

The plastic they use was not just a used because they had it around, most of it it is made of recycled bottles, it conforms to any shape, and it ca be layered many times, the plastic itself has been reused in rural communities as insulation, mock windows, sleeping bags patching for holes in shelter and even clothing. It is not a suitable material to burn, and shredding it makes it into finer particles, that have been show to bio-accumulat in higher lifeforms. If someone was to design a system that maintained a low enough melting temp, without burning the plastic, it could be melted into primitive shapes that would be items that would not need to be shipped to that destination/ or thrown away. If this plastic could, with controlled melting, into rectangles that then bolted together, one would be able to build any number of needed projects that could be used right away. the addition of some other materials would continue to strengthen this composite plastic. This all comes down to a tool that is very simple to use and one that prevents the plastic from burning and releasing toxic fumes. 

Because this is a simple plastic, it woud also be possible to press the wasted plastic and then add a compound that causes the plastic to  melt and hopefully be used in such a way so that you can have suitable "bricks" 

I feel that smelting (i use this term loosly) is the most logival solution to a "waste product" of shipping materials. I find that the paracord netting is too expensive and provides a far shorter useful lifespan that something like a plastic sheet that can be bolten together.