Proposal - on-farm composites

Proposal - on-farm composites Last changed: 2019/11/15 11:42
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SITUATION Proposal Name: On-farm production of timber-polymer composites for tools, fences and shelter Initiated By: Rory Submission date: date Background: Wood is among the earliest, cheapest and best-understood materials used by humans for tools, fences and shelter. It is lightweight, water-resistant, readily worked with simple tools, reasonably strong in compression and tension, and resistant to abrasion. Its availability is ubiquitous in most climates, and it can be readily farmed locally and sustainably. Wood has several drawbacks, however. It is flammable, vulnerable to attack by microorganisms, and most sustainably produced softwood timbers have sub-optimal elasticity, and impact strength. Plastics made from fossil fuels are both unsustainable and a waste disposal problem. Plastics have good resistance to microorganisms, and good elasticity and impact strength, but poor compression strength. Composites made from wood and plastic have properties often better than both parent materials. Composites are also an opportunity to recycle waste plastics, especially those used in packaging. These waste plastics are both difficult to biodegrade and energetically expensive to return to a recycling depot, especially in a low-density rural environment. Two plastics are of particular interest. Polystyrene (recycling code 6) is difficult to recycle, especially in its foamed applications, and is not accepted in curbside recycling. Polyethylene (LDPE recycling code 4 and HDPE recycling code 2) is ubiquitous in packaging, and while it is frequently recycled, the collection, transport, cleaning and reprocessing is energetically expensive. Both Polystyrene and Polyethylene melt at low temperatures (<~120C). When they burn, they emit a blue flame, and no dioxins (since they contain no halogens, only carbon, oxygen and hydrogen). The smoke is qualitatively similar to wood smoke in composition and toxicity. Polystyrene can be made mobile by dissolution in acetone, wood turpentine, or citrus essential oil. Polyethylene cannot, but both can be melted. Polystyrene can be decomposed back to the styrene monomer, and re-polymerised merely by heat. Timber can be impregnated by either polymer in the liquid phase, particularly under pressure and heat. The polymer fills the intracellular voids and tubules which comprise up to 40% of the volume of dry timber. The timber's cellulose, hemicellulose and lignin fibers remain intact (though lignin is a thermoplastic itself above 100C, and the resulting composites should be able to be bent and folded while hot). Bonding between the polymer and cellulose fibers requires small quantities of dispersant (sodium stearate/palmitate, aka soap) and bonding agent (styrene itself via depolymerisation with MgSO4, and a carboxylic acid via dehydration with Mg+ of an organic acid - acetic, citric or malic). Summary of proposed changes: This writer wishes to experiment with creating composites of radiata pine (both kiln-dried dowel and roughly-stripped branches) with plastic (polystyrene and polyethylene) using only simple and widely distributed tools. The first stage will involve experiments in reducing the plastics to liquid form (polystyrene/terpentine solution, styrene monomer, melted polystyrene and melted polyethylene). Waste plastics contain a diversity of additives - plasticisers, stabilisers, catalysts and promoters, so waste plastics from different sources will vary in the ease with which they can be made liquid. The second stage will be to soak and heat 300mm lengths of dowel and green pine in the different plastic liquids, then measure the properties of the resulting composites. A small quantity of Maleic Anhydride (corrosive and irritating, reacts with water) or Alkyl ketene dimer (may react only superficially) would be useful as a bonding promoter, will look into alternatives. How will this proposal advance the objectives of the Association? see Purposes of the Association What direct or indirect conflicts of interest does the initiating member or any other member have in this proposal? is there anything we should know about your connection to this? Will or might this proposal lead to the Association trading while insolvent? you are responsible for making sure your proposal won't run up debts or other liabilities What are the proposal's effects on other legal, reputational or financial risks? think broadly TIMINGS What date would the proposed project begin? date What date would it be in useful operation? date What date would it be retired? date RESOURCES What resources will it require? Money, materials, labour etc. For each resource, Will it be donated? By the initiating member, or another person? if it will not be donated, can it be supplied from goods on hand? if not, can it be purchased with existing Association funds? if none of these, who will be called on to pay for it? Can the required labour be sourced internally via the TaskMarket ? if not, can the required labour be recruited as members? if not, how will they be paid? Will the project require its own bank account? If yes, who will be registered to authorise transactions? What planned activities will the project require? What contingent activities will the project require? METHOD Step by step plan, with contingencies, and operating instructions OUTCOMES What resources and knowledge will the project produce?
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SITUATION

Proposal Name: On-farm production of timber-polymer composites for tools, fences and shelter

Initiated By: Rory

Submission date: date

Background:

Wood is among the earliest, cheapest and best-understood materials used by humans for tools, fences and shelter. It is lightweight, water-resistant, readily worked with simple tools, reasonably strong in compression and tension, and resistant to abrasion. Its availability is ubiquitous in most climates, and it can be readily farmed locally and sustainably.

Wood has several drawbacks, however. It is flammable, vulnerable to attack by microorganisms, and most sustainably produced softwood timbers have sub-optimal elasticity, and impact strength.

Plastics made from fossil fuels are both unsustainable and a waste disposal problem. Plastics have good resistance to microorganisms, and good elasticity and impact strength, but poor compression strength.

Composites made from wood and plastic have properties often better than both parent materials. Composites are also an opportunity to recycle waste plastics, especially those used in packaging. These waste plastics are both difficult to biodegrade and energetically expensive to return to a recycling depot, especially in a low-density rural environment.

Two plastics are of particular interest. Polystyrene (recycling code 6) is difficult to recycle, especially in its foamed applications, and is not accepted in curbside recycling. Polyethylene (LDPE recycling code 4 and HDPE recycling code 2) is ubiquitous in packaging, and while it is frequently recycled, the collection, transport, cleaning and reprocessing is energetically expensive.

Both Polystyrene and Polyethylene melt at low temperatures (<~120C). When they burn, they emit a blue flame, and no dioxins (since they contain no halogens, only carbon, oxygen and hydrogen). The smoke is qualitatively similar to wood smoke in composition and toxicity.

Polystyrene can be made mobile by dissolution in acetone, wood turpentine, or citrus essential oil. Polyethylene cannot, but both can be melted. Polystyrene can be decomposed back to the styrene monomer, and re-polymerised merely by heat.

Timber can be impregnated by either polymer in the liquid phase, particularly under pressure and heat. The polymer fills the intracellular voids and tubules which comprise up to 40% of the volume of dry timber. The timber's cellulose, hemicellulose and lignin fibers remain intact (though lignin is a thermoplastic itself above 100C, and the resulting composites should be able to be bent and folded while hot).

Bonding between the polymer and cellulose fibers requires small quantities of dispersant (sodium stearate/palmitate, aka soap) and bonding agent (styrene itself via depolymerisation with MgSO4, and a carboxylic acid via dehydration with Mg+ of an organic acid - acetic, citric or malic).

Summary of proposed changes:

This writer wishes to experiment with creating composites of radiata pine (both kiln-dried dowel and roughly-stripped branches) with plastic (polystyrene and polyethylene) using only simple and widely distributed tools.

The first stage will involve experiments in reducing the plastics to liquid form (polystyrene/terpentine solution, styrene monomer, melted polystyrene and melted polyethylene). Waste plastics contain a diversity of additives - plasticisers, stabilisers, catalysts and promoters, so waste plastics from different sources will vary in the ease with which they can be made liquid.

The second stage will be to soak and heat 300mm lengths of dowel and green pine in the different plastic liquids, then measure the properties of the resulting composites. A small quantity of Maleic Anhydride (corrosive and irritating, reacts with water) or Alkyl ketene dimer (may react only superficially) would be useful as a bonding promoter, will look into alternatives.

How will this proposal advance the objectives of the Association? see Purposes of the Association

What direct or indirect conflicts of interest does the initiating member or any other member have in this proposal? is there anything we should know about your connection to this?

Will or might this proposal lead to the Association trading while insolvent? you are responsible for making sure your proposal won't run up debts or other liabilities

What are the proposal's effects on other legal, reputational or financial risks? think broadly

Proposal - on-farm composites

SITUATION

TIMINGS

RESOURCES

METHOD

OUTCOMES