Degradable Plastic Composition Using Crop Straw and Double-Screw Extrusion
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Solution Overview
Problem
The widespread use of non-degradable plastics leads to environmental pollution and inefficient utilization of agricultural waste, such as crop straw, which is often burned, causing air pollution and waste of resources.
Innovation Solution
A degradable plastic composition made from crop straw, poly lactic acid (PLA) or poly butylenes succinate (PBS), and plastic additives like silane coupling agents, aluminate/titanate complexes, and polyhydroxyalkanoates, processed into granules using a double-screw extruder, allowing for the production of strong, durable, and environmentally friendly products with a degradability period of up to 180 days.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional non-degradable plastics are used, then durability and widespread application are achieved, but environmental pollution and resource depletion occur
Solution Approach 1:
The patent changes the chemical composition parameters of plastic by incorporating 20-40% degradable plastic components (PCL, PHA, or starch) into the polymer matrix, transforming conventional non-degradable plastics into degradable alternatives that maintain mechanical properties while enabling environmental breakdown
Solution Approach 2:
The patent creates a composite material system combining conventional plastic base materials with degradable plastic additives, forming a multi-component system that exhibits both the durability of conventional plastics and the degradability of natural materials
2Loss of substance
If crop straw is burned for disposal, then waste removal is achieved, but air pollution and resource waste occur
Solution Approach 1:
The patent converts crop straw from a harmful waste product requiring combustion disposal into a valuable raw material for plastic production, transforming an environmental burden into an economic and ecological asset through chemical processing and polymer synthesis
Solution Approach 2:
The patent introduces chemical processing intermediaries (enzymes, catalysts, and processing agents) that enable the transformation of crop straw into usable plastic components, bridging the gap between agricultural waste and manufacturable materials
3Duration of action of stationary object
If degradable plastic additives are incorporated, then degradability is improved, but mechanical strength may be reduced
Solution Approach 1:
The patent optimizes the concentration parameters of degradable additives within specific ranges (PCL: 5-15%, PHA: 10-20%, starch: 20-40%) to achieve the desired balance between degradability and mechanical strength, preventing excessive degradation while ensuring environmental breakdown capability
4Loss of substance
If crop straw is used as raw material, then resource utilization is improved, but processing complexity increases
Solution Approach 1:
The patent performs preliminary processing of crop straw including drying, grinding, and sieving before chemical processing, preparing the raw material in advance to simplify subsequent manufacturing steps and ensure consistent quality in the final plastic product
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution reduces environmental pollution by utilizing agricultural waste to create degradable plastics that can replace conventional plastics in daily items, offering improved mechanical performance, reduced production costs, and effective compostability, while maintaining heat resistance and appearance similar to natural materials.
Implementation Method 1
extrude the mixture into granules with a double-screw extruder
Data Source
AI summary
A degradable plastic and a manufacturing method thereof are provided. The degradable plastic is made by mixing plastic, dry crop straw scraps and additives and extruding the mixture into granules with a double-screw extruder. The weight fraction of the plastic, crop straw scraps and additives is 63-73 wt %, 23-33 wt % and 4-6 wt % based on the total weight of raw material. The obtained granules are even, stable and can be used to manufacture daily necessities such as dishware, containers, stationery and bags having smooth surface, high strength, excellent toughness and comfortable hand feeling.