21st Century Green Tech

1. Want a Building to Last 1,500 Years? Add Sticky Rice
2. Scientists Make CO2-Capturing, BPA-Free Plastic

Want a Building to Last 1,500 Years? Add Sticky Rice

2010-06-02 17:32

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sticky-rice
Creating sustainable, long-lasting structures is at the core of environmentally-friendly architecture. Many researchers have been working on a better cement, but what if all you need to make a durable structure is available for take-out?

Recent studies of Ming Dynasty-era structures in China found that the secret to their lasting strength and stability is the mixing of sticky rice into the mortar.

Chinese builders started adding starchy sticky rice soup to their lime mortar mixtures around 1,500 years ago. The builders found that it added to the mortar's strength and they were right. Scientists studying tombs, pagodas and city walls still standing from that time found that they all included this magic ingredient -- many even withstood earthquakes.

So, what makes sticky rice such a perfect addition to mortar? Well, specifically it's the amylopectin, a polysaccharide found in starchy foods, that combines with the calcium carbonate in the lime and forms an ultra-strength mortar. The scientists tested other mortar recipes and found that the sticky rice mixture was the best for restoring ancient structures.

While, it's unlikely that American builders will start stocking up on rice for their construction projects, this finding does clue us in on how organic materials can add to the strength of buildings and may hopefully lead to longer-lasting structures.

via Inhabitat

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Scientists Make CO2-Capturing, BPA-Free Plastic

2010-06-02 16:57

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Here's a neat discovery that solves two problems at once: scientists have identified classes of organic chemicals that can capture CO2 from the atmosphere and then be used to make safe (BPA-free) plastics.

BPA, a chemical with a growing list of health concerns, is commonly used in rigid polycarbonate plastics (about 2.7 million tons are made every year). Researchers at the Institute of Bioengineering and Nanotechnology in Singapore have found a way to make a BPA-free polycarbonate plastic through a process using chemicals called imidazoliums and N-heterocyclic carbenes that "grab" CO2 molecules and bond them with epoxide molecules.

The process removes CO2 from the atmosphere and makes a safe form of plastic for drinking bottles, CDs and other typical BPA-laced containers. If that weren't enough, this process also gets rid of the need for petroleum in the manufacture of plastics, which would reduce the material's carbon footprint even further.

via Yale e360