Development of renewable and hydrolytically degradable polymers from biomass-based monomers

Renewable polymers (bioplastics) offer an alternative to petroleum-based polymers and reduced environmental impact through decreased petroleum dependence and a sustainable product lifecycle via renewable, biomass-derived monomers and completely degradable polymers. Applying green chemistry principles, melt polycondensations of 1,3-propanediol with malonic acid and 1,3-propanediol with itaconic acid were performed to produce poly(trimethylene malonte) (PTM) and poly(trimethylene itaconate) (PTI), respectively. Aluminum chloride was used as the catalyst and reaction temperatures from 125-175 °C and reaction times from 2-32 h were attempted in order to produce high yields and molecular weights (Mw). Gravimetric yields ranged from 20-95 wt.% for PTM and 20-85 wt.% for PTI. Both PTM and PTI contained ester and ether backbone bonds, as determined by Fourier transform infrared and nuclear magnetic resonance spectroscopy. Gel permeation chromatography showed both PTM and PTI to have a bi-modal Mw distributions centered at 1.4±0.1 kDa and 35±3 kDa for PTM and 1.0±0.1 kDa and 38±2 kDa for PTI. For PTM, a Tg of -64 °C and a Tm of 29 °C was identified using differential scanning calorimetry (DSC). A crystallization temperature for PTI was found at ~160 °C using DSC. A hydrolytic degradation study was performed at 25 °C on PTM and PTI in pH 5.4, 7, 9, and 11 aqueous solutions for up to 4 weeks. The introduction of K+ ions (in the KOH aq. solutions) interfered with the AAC2 and AAL1 ester hydrolysis mechanisms through acid-base interactions. PTM was found to be susceptible to hydrolytic degradation and lost ~37 wt.% through ester hydrolysis and showed a molecular weight reduction of ~0.8 kDa over 10,000 min for a pH range of 7 to 11. PTI was also found to be susceptible to hydrolytic degradation with ~22 wt.% decrease through ester hydrolysis and molecular weight reduction of ~0.25 kDa over 10,000 min for a pH range of 7 to 11. PTM is a low molecular weight, saturated, linear copolymer and PTI is a low molecular weight, unsaturated, branched copolymer. Both PTM and PTI are renewable copolymers produced using green chemistry and mild reactions conditions and were found to be susceptible to hydrolytic degradation

Nitrogen and phosphorus enrichment effects on CO2 and methane fluxes from an upland ecosystem

Reactive nitrogen (N) deposition can affect many ecosystem processes, particularly in oligotrophic habitats, and is expected to affect soil C storage potential through increases in microbial decomposition rate as a consequence of greater N availability. Increased N availability may also result in changes in the principal limitations on ecosystem productivity. Phosphorus (P) limitation may constrain productivity in instances of high N deposition, yet ecosystem responses to P availability are poorly understood. This study investigated CO2 and CH4 flux responses to N and P enrichment using both short- (1 year) and long-term (16 year) nutrient addition experiments. We hypothesised that the addition of either N or P will increase CO2 and CH4 fluxes, since both plant production and microbial activity are likely to increase with alleviation from nutrient limitation. This study demonstrated the modification of C fluxes from N and P enrichment, with differing results subject to the duration of nutrient addition. On average, relative to control, the addition of N alone inhibited CO2 flux in the short-term (− 9%) but considerably increased CO2 emissions in the long-term (+ 35%), reduced CH4 uptake in the short term (− 90%) and reduced CH4 emission in the long term (− 94%). Phosphorus addition increased CO2 and CH4 emission in the short term (+ 20% and + 184% respectively), with diminishing effect into the long term, suggesting microbial communities at these sites are P limited. Whilst a full C exchange budget was not examined in the experiment, the potential for soil C storage loss with long-term nutrient enrichment is demonstrated and indicates that P addition, where P is a limiting factor, may have an adverse influence on upland soil C content

Environment Crises

Report consists of three different parts(print) 91 p. ; 28 cm.Preface -- List of Tables -- Part A: Dimensions of Community Leadership and the Definition of Water Resources Problems -- Part B: Factors in the Community Perception of Water Resource Problems -- Part C: A Sociologist Looks at Water Resources Researc

P4_3 - It's a Mad Lego World

In this paper, we investigate what would happen to the orbital radius of the Moon if the Earth was made of Lego. We found that for an Earth of equal radius and therefore equal volume, and not considering orbital velocity, the orbital radius of the Moon would increase from 384,000km to 1.98*10^6km

P4_6 Horses make the world go round

The aim of this paper was to determine the feasibility of some factors of the Helios mythology, and to find the force that would be required to accelerate Earth from rest to its current angular velocity. We found that the force required to achieve this in a single day, is 1.39 × 1022 N which is extremely large considering Helios is only using four winged horses. This combined with there being no practical way to apply this force to the Earth, led to us concluding that it was not feasible

P4_1 Sunday Roast the 'Easy' Way.

This paper investigates the difference in time it would take to cook multiple common food items from a roast meal in an ’Easy Bake’ Oven, opposed to a standard kitchen oven. We found that when cooking a 1.00kg chicken and 1.00kg of roast potatoes it saved the chef 31.0mins and 5.60mins, respectively. However, due to the size of an Easy Bake Oven and the practicality of this, the standard kitchen oven continues to be the ’Easy’ way to cook a Sunday roast