不同稳定剂对天然胶乳胶膜物理机械性能的影响

Effects of Different Stabilizers on the Properties of Natural Rubber Latex Films

天然胶乳稳定剂不仅会影响胶乳的胶体稳定性,对胶膜性能也具有显著影响。本研究选用氢氧化钾(KOH)、氨、十二烷基硫酸钠(SDS)和月桂酸钾4种稳定剂添加到浓缩胶乳中,并制备预硫化配合胶乳,研究4种稳定剂对浓缩胶乳成膜性能、胶膜硫化特性及物理机械性能的影响。结果表明:4种稳定剂中对浓缩胶乳胶膜性能影响最大的是KOH,KOH会提高干胶膜的门尼粘度;降低干胶膜收缩率、拉伸强度、定伸应力、断裂伸长率、撕裂强度和硬度等力学性能;同时缩短硫化胶膜的t_(10)、t_(50)和t_(90)时间,转矩差值先升后降,定伸应力有所提升,但拉伸强度、断裂伸长率和硬度均会降低,而撕裂强度呈先升后降的趋势。随着氨用量的提高,干胶膜收缩率、拉伸强度、断裂伸长率和撕裂强度均呈先升后降的趋势;硫化胶膜t_(90)和胶膜收缩率有所升高;拉伸强度、定伸应力同样存在先升后降的趋势。随着SDS用量的提高,浓缩胶乳干胶膜拉伸强度存在先降后升的趋势;硫化胶膜的转矩差值有一定程度的升高;t_(50)和t_(90)比较稳定,并在SDS用量超过0.3%后明显上升,即硫化速度降低;硫化胶膜收缩率快速下降,下降幅度较大。随着月桂酸钾用量的提高,干胶膜门尼粘度和收缩率下降幅度很大;断裂伸长率和撕裂强度有一定提升。硫化胶膜的转矩差值升高幅度最大;胶膜收缩率明显降低,撕裂强度呈先升后降的趋势,其他指标稳定,变化幅度较小。

In this study,four stabilizers including potassium hydroxide(KOH),ammonia,sodium dodecyl sulfate(SDS)and potassium laurate were added to concentrated natural rubber latex(CNRL).The performance of the CNRL film was most affected by the amount of KOH.With the increase of KOH content,the Mooney viscosity of the film increased and the shrinkage rate decreased.The tensile strength,tensile stress,elongation at break,tear strength and hardness all de-creased rapidly.With the increase dosage of potassium laurate,the Mooney viscosity and the shrinkage rate of the raw rubber film decreased to a certain extent.The tensile strength had a tendency to increase first and then decrease.With the increase of ammonia consumption,there was also a trend of first rising and then falling.More dosage of sodium dodecyl sulfate(SDS)would lead to lower tear strength of the raw rubber film.The performance of the vulcanizate film was also most affected by the amount of KOH.With the increase of KOH dosage,the ML and MH of the vulcanizate film would increase.The t_(10),t_(50) and t_(90) would be shortened,and the film shrinkage was reduced.In addition,the tensile strength and elongation at break of the rubber film decreased.The tensile stress and tear strength had a trend of increas-ing first and then decreasing.As the amount of ammonia increased,the t_(90) of the vulcanizate film would increase.The shrinkage rate of the film increasesd,and the tensile stress first increased and then decreased.With the increase of the amount of SDS,the t_(90) of the vulcanizate film would be prolonged and the film shrinkage was reduced.With the in-crease of potassium laurate dosage,the ML and MH of the vulcanizate film would increase,the film shrinkage was re-duced,and the tear strength showed a trend of increasing first and then decreasing.It could be seen from the hardness change that the film would become soft after adding KOH and the hardness would be greatly reduced.The Mooney viscosity of the film was greatly improved.After the addition of potassium laurate,the Mooney viscosity of the film decreased significantly,but the hardness of the film did not change much.From the perspective of vulcanization,after adding KOH,the vulcanization degree of the rubber film increased,and the vulcanization time decreased.KOH had a certain promotion and promotion effect on the vulcanization degree of the film.However,combined with the mechanical properties of the vulcanized film.The tensile stress of the film increased after adding KOH,but the tensile strength,tear strength and elongation were significantly reduced.However,the film strength changed little when the other three stabi-lizers were added.